Analysis

  • max time kernel
    2s
  • max time network
    110s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-20231215-en
  • resource tags

    arch:x64arch:x86image:win10v2004-20231215-enlocale:en-usos:windows10-2004-x64system
  • submitted
    04/01/2024, 13:54

General

  • Target

    41098f5762dc04369ebf2e54a1efa540.exe

  • Size

    2.0MB

  • MD5

    41098f5762dc04369ebf2e54a1efa540

  • SHA1

    0e541de9b3dd4ea228226bad5f3a93e6911342f8

  • SHA256

    4d3a6bd44756de82a2e5a60a082445ae007ae8b3f9019d1868b06882f1cb33a4

  • SHA512

    441b824709b727705d597fe1e9c4be4df6810e9ff1365f8110b8fb9e21d327ee96d9ae942875fa4cf71f5beea563391d08b16643bc4188223274ad233ac101c7

  • SSDEEP

    24576:UuhaCeZJ8NI8xeZJ8NI8xeZJ8NI8xeZJ8NI8xeZJ8NI8xeZJ8NI8L4:bW82828282828s

Score
10/10

Malware Config

Signatures

  • Modifies visibility of file extensions in Explorer 2 TTPs 1 IoCs
  • Blocks application from running via registry modification 17 IoCs

    Adds application to list of disallowed applications.

  • Sets file execution options in registry 2 TTPs 20 IoCs
  • Drops file in System32 directory 1 IoCs
  • Drops file in Windows directory 5 IoCs
  • Launches sc.exe 8 IoCs

    Sc.exe is a Windows utlilty to control services on the system.

  • Runs net.exe
  • Runs regedit.exe 1 IoCs
  • Suspicious use of SetWindowsHookEx 1 IoCs
  • Suspicious use of WriteProcessMemory 57 IoCs
  • Views/modifies file attributes 1 TTPs 16 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\41098f5762dc04369ebf2e54a1efa540.exe
    "C:\Users\Admin\AppData\Local\Temp\41098f5762dc04369ebf2e54a1efa540.exe"
    1⤵
    • Drops file in System32 directory
    • Drops file in Windows directory
    • Suspicious use of SetWindowsHookEx
    • Suspicious use of WriteProcessMemory
    PID:4784
    • C:\Windows\SysWOW64\net.exe
      net.exe start schedule /y
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:2160
    • C:\Windows\SysWOW64\cmd.exe
      C:\Windows\system32\cmd.exe /c C:\Windows\system32\Option.bat
      2⤵
        PID:1300
      • C:\Windows\SysWOW64\sc.exe
        C:\Windows\system32\sc.exe config srservice start= disabled
        2⤵
        • Launches sc.exe
        PID:4532
      • C:\Windows\SysWOW64\regedit.exe
        regedit.exe /s C:\Windows\regedt32.sys
        2⤵
        • Modifies visibility of file extensions in Explorer
        • Blocks application from running via registry modification
        • Sets file execution options in registry
        • Runs regedit.exe
        PID:4528
      • C:\Windows\system\KavUpda.exe
        C:\Windows\system\KavUpda.exe
        2⤵
          PID:4444
          • C:\Windows\SysWOW64\net.exe
            net.exe stop srservice /y
            3⤵
              PID:2776
              • C:\Windows\SysWOW64\net1.exe
                C:\Windows\system32\net1 stop srservice /y
                4⤵
                  PID:3140
              • C:\Windows\SysWOW64\reg.exe
                C:\Windows\system32\reg.exe delete "hklm\SYSTEM\ControlSet001\Control\SafeBoot\Network\{4D36E967-E325-11CE-BFC1-08002BE10318}" /f
                3⤵
                  PID:1584
                • C:\Windows\SysWOW64\cmd.exe
                  cmd /c rmdir F:\Autorun.inf /s /q
                  3⤵
                    PID:768
                  • C:\Windows\SysWOW64\cmd.exe
                    cmd /c attrib -s -h -r F:\Autorun.inf\*.* /s /d
                    3⤵
                      PID:1512
                    • C:\Windows\SysWOW64\reg.exe
                      C:\Windows\system32\reg.exe delete "hklm\SYSTEM\ControlSet001\Control\SafeBoot\Minimal\{4D36E967-E325-11CE-BFC1-08002BE10318}" /f
                      3⤵
                        PID:1936
                      • C:\Windows\SysWOW64\sc.exe
                        C:\Windows\system32\sc.exe config srservice start= disabled
                        3⤵
                        • Launches sc.exe
                        PID:4852
                      • C:\Windows\SysWOW64\sc.exe
                        C:\Windows\system32\sc.exe config wscsvc start= disabled
                        3⤵
                        • Launches sc.exe
                        PID:2924
                      • C:\Windows\SysWOW64\sc.exe
                        C:\Windows\system32\sc.exe config SharedAccess start= disabled
                        3⤵
                        • Launches sc.exe
                        PID:4148
                      • C:\Windows\SysWOW64\sc.exe
                        C:\Windows\system32\sc.exe config srservice start= disabled
                        3⤵
                        • Launches sc.exe
                        PID:800
                      • C:\Windows\SysWOW64\net.exe
                        net.exe stop 360timeprot /y
                        3⤵
                          PID:3464
                        • C:\Windows\SysWOW64\net.exe
                          net.exe stop wuauserv /y
                          3⤵
                            PID:2540
                          • C:\Windows\SysWOW64\net.exe
                            net.exe stop sharedaccess /y
                            3⤵
                              PID:5036
                            • C:\Windows\SysWOW64\net.exe
                              net.exe stop wscsvc /y
                              3⤵
                                PID:1616
                              • C:\Windows\SysWOW64\cmd.exe
                                cmd /c at 1:59:52 PM C:\Windows\Sysinf.bat
                                3⤵
                                  PID:3336
                                • C:\Windows\SysWOW64\cmd.exe
                                  cmd /c at 1:56:52 PM C:\Windows\Sysinf.bat
                                  3⤵
                                    PID:3520
                                  • C:\Windows\SysWOW64\At.exe
                                    At.exe 1:57:50 PM C:\Windows\Help\HelpCat.exe
                                    3⤵
                                      PID:3300
                                    • C:\Windows\SysWOW64\cmd.exe
                                      cmd /c rmdir C:\Autorun.inf /s /q
                                      3⤵
                                        PID:3436
                                      • C:\Windows\SysWOW64\cmd.exe
                                        cmd /c attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                        3⤵
                                          PID:3488
                                        • C:\Windows\SysWOW64\cmd.exe
                                          cmd /c rmdir F:\Autorun.inf /s /q
                                          3⤵
                                            PID:3136
                                          • C:\Windows\SysWOW64\cmd.exe
                                            cmd /c attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                            3⤵
                                              PID:1692
                                            • C:\Windows\SysWOW64\cmd.exe
                                              cmd /c rmdir C:\Autorun.inf /s /q
                                              3⤵
                                                PID:4244
                                              • C:\Windows\SysWOW64\cmd.exe
                                                cmd /c attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                3⤵
                                                  PID:1220
                                                • C:\Windows\SysWOW64\cmd.exe
                                                  cmd /c rmdir F:\Autorun.inf /s /q
                                                  3⤵
                                                    PID:4152
                                                  • C:\Windows\SysWOW64\cmd.exe
                                                    cmd /c attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                    3⤵
                                                      PID:4004
                                                    • C:\Windows\SysWOW64\cmd.exe
                                                      cmd /c rmdir C:\Autorun.inf /s /q
                                                      3⤵
                                                        PID:3900
                                                      • C:\Windows\SysWOW64\cmd.exe
                                                        cmd /c attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                        3⤵
                                                          PID:432
                                                        • C:\Windows\SysWOW64\cmd.exe
                                                          cmd /c rmdir F:\Autorun.inf /s /q
                                                          3⤵
                                                            PID:2808
                                                          • C:\Windows\SysWOW64\cmd.exe
                                                            cmd /c attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                            3⤵
                                                              PID:4156
                                                            • C:\Windows\SysWOW64\cmd.exe
                                                              cmd /c rmdir C:\Autorun.inf /s /q
                                                              3⤵
                                                                PID:4224
                                                              • C:\Windows\SysWOW64\cmd.exe
                                                                cmd /c attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                3⤵
                                                                  PID:4628
                                                                • C:\Windows\SysWOW64\cmd.exe
                                                                  cmd /c attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                  3⤵
                                                                    PID:1384
                                                                    • C:\Windows\SysWOW64\attrib.exe
                                                                      attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                      4⤵
                                                                      • Views/modifies file attributes
                                                                      PID:2816
                                                                  • C:\Windows\SysWOW64\cmd.exe
                                                                    cmd /c rmdir F:\Autorun.inf /s /q
                                                                    3⤵
                                                                      PID:1412
                                                                    • C:\Windows\SysWOW64\cmd.exe
                                                                      cmd /c rmdir C:\Autorun.inf /s /q
                                                                      3⤵
                                                                        PID:1420
                                                                      • C:\Windows\SysWOW64\cmd.exe
                                                                        cmd /c attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                        3⤵
                                                                          PID:4448
                                                                        • C:\Windows\SysWOW64\cmd.exe
                                                                          cmd /c rmdir F:\Autorun.inf /s /q
                                                                          3⤵
                                                                            PID:1232
                                                                          • C:\Windows\SysWOW64\cmd.exe
                                                                            cmd /c attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                            3⤵
                                                                              PID:1584
                                                                            • C:\Windows\SysWOW64\cmd.exe
                                                                              cmd /c rmdir C:\Autorun.inf /s /q
                                                                              3⤵
                                                                                PID:4124
                                                                              • C:\Windows\SysWOW64\cmd.exe
                                                                                cmd /c attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                3⤵
                                                                                  PID:3196
                                                                                • C:\Windows\SysWOW64\cmd.exe
                                                                                  cmd /c rmdir F:\Autorun.inf /s /q
                                                                                  3⤵
                                                                                    PID:3616
                                                                                  • C:\Windows\SysWOW64\cmd.exe
                                                                                    cmd /c attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                    3⤵
                                                                                      PID:2860
                                                                                    • C:\Windows\SysWOW64\cmd.exe
                                                                                      cmd /c rmdir C:\Autorun.inf /s /q
                                                                                      3⤵
                                                                                        PID:400
                                                                                      • C:\Windows\SysWOW64\cmd.exe
                                                                                        cmd /c attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                        3⤵
                                                                                          PID:856
                                                                                        • C:\Windows\SysWOW64\cmd.exe
                                                                                          cmd /c rmdir F:\Autorun.inf /s /q
                                                                                          3⤵
                                                                                            PID:4380
                                                                                          • C:\Windows\SysWOW64\cmd.exe
                                                                                            cmd /c attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                            3⤵
                                                                                              PID:1604
                                                                                            • C:\Windows\SysWOW64\cmd.exe
                                                                                              cmd /c rmdir C:\Autorun.inf /s /q
                                                                                              3⤵
                                                                                                PID:1316
                                                                                              • C:\Windows\SysWOW64\cmd.exe
                                                                                                cmd /c attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                3⤵
                                                                                                  PID:3968
                                                                                              • C:\Windows\SysWOW64\reg.exe
                                                                                                C:\Windows\system32\reg.exe delete "hklm\SYSTEM\ControlSet001\Control\SafeBoot\Network\{4D36E967-E325-11CE-BFC1-08002BE10318}" /f
                                                                                                2⤵
                                                                                                  PID:2804
                                                                                                • C:\Windows\SysWOW64\reg.exe
                                                                                                  C:\Windows\system32\reg.exe delete "hklm\SYSTEM\ControlSet001\Control\SafeBoot\Minimal\{4D36E967-E325-11CE-BFC1-08002BE10318}" /f
                                                                                                  2⤵
                                                                                                    PID:3444
                                                                                                  • C:\Windows\SysWOW64\sc.exe
                                                                                                    C:\Windows\system32\sc.exe config wscsvc start= disabled
                                                                                                    2⤵
                                                                                                    • Launches sc.exe
                                                                                                    PID:3464
                                                                                                    • C:\Windows\SysWOW64\net1.exe
                                                                                                      C:\Windows\system32\net1 stop 360timeprot /y
                                                                                                      3⤵
                                                                                                        PID:3896
                                                                                                    • C:\Windows\SysWOW64\sc.exe
                                                                                                      C:\Windows\system32\sc.exe config SharedAccess start= disabled
                                                                                                      2⤵
                                                                                                      • Launches sc.exe
                                                                                                      PID:880
                                                                                                    • C:\Windows\SysWOW64\sc.exe
                                                                                                      C:\Windows\system32\sc.exe config srservice start= disabled
                                                                                                      2⤵
                                                                                                      • Launches sc.exe
                                                                                                      PID:2152
                                                                                                    • C:\Windows\SysWOW64\net.exe
                                                                                                      net.exe stop 360timeprot /y
                                                                                                      2⤵
                                                                                                        PID:2236
                                                                                                      • C:\Windows\SysWOW64\net.exe
                                                                                                        net.exe stop srservice /y
                                                                                                        2⤵
                                                                                                          PID:3192
                                                                                                        • C:\Windows\SysWOW64\net.exe
                                                                                                          net.exe stop wuauserv /y
                                                                                                          2⤵
                                                                                                            PID:4648
                                                                                                          • C:\Windows\SysWOW64\net.exe
                                                                                                            net.exe stop sharedaccess /y
                                                                                                            2⤵
                                                                                                              PID:1512
                                                                                                              • C:\Windows\SysWOW64\attrib.exe
                                                                                                                attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                                                3⤵
                                                                                                                • Views/modifies file attributes
                                                                                                                PID:2396
                                                                                                            • C:\Windows\SysWOW64\net.exe
                                                                                                              net.exe stop wscsvc /y
                                                                                                              2⤵
                                                                                                                PID:4996
                                                                                                              • C:\Windows\SysWOW64\cmd.exe
                                                                                                                cmd /c at 1:59:49 PM C:\Windows\Sysinf.bat
                                                                                                                2⤵
                                                                                                                  PID:2792
                                                                                                                • C:\Windows\SysWOW64\cmd.exe
                                                                                                                  cmd /c at 1:56:49 PM C:\Windows\Sysinf.bat
                                                                                                                  2⤵
                                                                                                                    PID:856
                                                                                                                  • C:\Users\Admin\AppData\Local\Temp\41098f5762dc04369ebf2e54a1efa540~4.exe
                                                                                                                    41098f5762dc04369ebf2e54a1efa540~4.exe
                                                                                                                    2⤵
                                                                                                                      PID:2088
                                                                                                                    • C:\Windows\SysWOW64\At.exe
                                                                                                                      At.exe 1:57:47 PM C:\Windows\Help\HelpCat.exe
                                                                                                                      2⤵
                                                                                                                        PID:828
                                                                                                                    • C:\Windows\SysWOW64\net1.exe
                                                                                                                      C:\Windows\system32\net1 start schedule /y
                                                                                                                      1⤵
                                                                                                                        PID:948
                                                                                                                      • C:\Windows\SysWOW64\net1.exe
                                                                                                                        C:\Windows\system32\net1 stop srservice /y
                                                                                                                        1⤵
                                                                                                                          PID:1108
                                                                                                                        • C:\Windows\SysWOW64\at.exe
                                                                                                                          at 1:59:49 PM C:\Windows\Sysinf.bat
                                                                                                                          1⤵
                                                                                                                            PID:4040
                                                                                                                          • C:\Windows\SysWOW64\net1.exe
                                                                                                                            C:\Windows\system32\net1 stop sharedaccess /y
                                                                                                                            1⤵
                                                                                                                              PID:804
                                                                                                                            • C:\Windows\SysWOW64\net1.exe
                                                                                                                              C:\Windows\system32\net1 start schedule /y
                                                                                                                              1⤵
                                                                                                                                PID:1508
                                                                                                                              • C:\Windows\SysWOW64\net.exe
                                                                                                                                net.exe start schedule /y
                                                                                                                                1⤵
                                                                                                                                  PID:4356
                                                                                                                                • C:\Windows\SysWOW64\cmd.exe
                                                                                                                                  C:\Windows\system32\cmd.exe /c C:\Windows\system32\Option.bat
                                                                                                                                  1⤵
                                                                                                                                    PID:3876
                                                                                                                                  • C:\Windows\SysWOW64\net1.exe
                                                                                                                                    C:\Windows\system32\net1 stop wscsvc /y
                                                                                                                                    1⤵
                                                                                                                                      PID:4596
                                                                                                                                    • C:\Windows\SysWOW64\net1.exe
                                                                                                                                      C:\Windows\system32\net1 stop wuauserv /y
                                                                                                                                      1⤵
                                                                                                                                        PID:4148
                                                                                                                                        • C:\Windows\System32\Conhost.exe
                                                                                                                                          \??\C:\Windows\system32\conhost.exe 0xffffffff -ForceV1
                                                                                                                                          2⤵
                                                                                                                                            PID:896
                                                                                                                                        • C:\Windows\SysWOW64\net1.exe
                                                                                                                                          C:\Windows\system32\net1 stop 360timeprot /y
                                                                                                                                          1⤵
                                                                                                                                            PID:2800
                                                                                                                                          • C:\Windows\SysWOW64\at.exe
                                                                                                                                            at 1:56:49 PM C:\Windows\Sysinf.bat
                                                                                                                                            1⤵
                                                                                                                                              PID:896
                                                                                                                                            • C:\Windows\System32\Conhost.exe
                                                                                                                                              \??\C:\Windows\system32\conhost.exe 0xffffffff -ForceV1
                                                                                                                                              1⤵
                                                                                                                                              • Suspicious use of WriteProcessMemory
                                                                                                                                              PID:856
                                                                                                                                              • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                                                                2⤵
                                                                                                                                                • Views/modifies file attributes
                                                                                                                                                PID:3196
                                                                                                                                            • C:\Windows\SysWOW64\net1.exe
                                                                                                                                              C:\Windows\system32\net1 stop wuauserv /y
                                                                                                                                              1⤵
                                                                                                                                                PID:1488
                                                                                                                                              • C:\Windows\SysWOW64\at.exe
                                                                                                                                                at 1:59:52 PM C:\Windows\Sysinf.bat
                                                                                                                                                1⤵
                                                                                                                                                  PID:3644
                                                                                                                                                • C:\Windows\SysWOW64\at.exe
                                                                                                                                                  at 1:56:52 PM C:\Windows\Sysinf.bat
                                                                                                                                                  1⤵
                                                                                                                                                    PID:3552
                                                                                                                                                  • C:\Windows\SysWOW64\net1.exe
                                                                                                                                                    C:\Windows\system32\net1 stop wscsvc /y
                                                                                                                                                    1⤵
                                                                                                                                                      PID:1640
                                                                                                                                                    • C:\Windows\SysWOW64\net1.exe
                                                                                                                                                      C:\Windows\system32\net1 stop sharedaccess /y
                                                                                                                                                      1⤵
                                                                                                                                                        PID:3640
                                                                                                                                                      • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                        attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                                                                        1⤵
                                                                                                                                                        • Views/modifies file attributes
                                                                                                                                                        PID:1584
                                                                                                                                                        • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                          attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                                                                                          2⤵
                                                                                                                                                          • Views/modifies file attributes
                                                                                                                                                          PID:740
                                                                                                                                                      • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                        attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                                                                                        1⤵
                                                                                                                                                        • Views/modifies file attributes
                                                                                                                                                        PID:2024
                                                                                                                                                      • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                        attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                                                                        1⤵
                                                                                                                                                        • Views/modifies file attributes
                                                                                                                                                        PID:3584
                                                                                                                                                      • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                        attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                                                                                        1⤵
                                                                                                                                                        • Views/modifies file attributes
                                                                                                                                                        PID:1636
                                                                                                                                                      • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                        attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                                                                        1⤵
                                                                                                                                                        • Views/modifies file attributes
                                                                                                                                                        PID:3592
                                                                                                                                                      • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                        attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                                                                                        1⤵
                                                                                                                                                        • Views/modifies file attributes
                                                                                                                                                        PID:4996
                                                                                                                                                      • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                        attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                                                                        1⤵
                                                                                                                                                        • Views/modifies file attributes
                                                                                                                                                        PID:3764
                                                                                                                                                      • C:\Windows\System32\Conhost.exe
                                                                                                                                                        \??\C:\Windows\system32\conhost.exe 0xffffffff -ForceV1
                                                                                                                                                        1⤵
                                                                                                                                                          PID:3464
                                                                                                                                                        • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                          attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                                                                          1⤵
                                                                                                                                                          • Views/modifies file attributes
                                                                                                                                                          PID:3972
                                                                                                                                                        • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                          attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                                                                          1⤵
                                                                                                                                                          • Views/modifies file attributes
                                                                                                                                                          PID:4012
                                                                                                                                                        • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                          attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                                                                                          1⤵
                                                                                                                                                          • Views/modifies file attributes
                                                                                                                                                          PID:2160
                                                                                                                                                        • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                          attrib -s -h -r F:\Autorun.inf\*.* /s /d
                                                                                                                                                          1⤵
                                                                                                                                                          • Views/modifies file attributes
                                                                                                                                                          PID:1112
                                                                                                                                                        • C:\Windows\SysWOW64\attrib.exe
                                                                                                                                                          attrib -s -h -r C:\Autorun.inf\*.* /s /d
                                                                                                                                                          1⤵
                                                                                                                                                          • Views/modifies file attributes
                                                                                                                                                          PID:2480

                                                                                                                                                        Network

                                                                                                                                                              MITRE ATT&CK Enterprise v15

                                                                                                                                                              Replay Monitor

                                                                                                                                                              Loading Replay Monitor...

                                                                                                                                                              Downloads

                                                                                                                                                              • memory/4784-0-0x0000000000400000-0x0000000000436000-memory.dmp

                                                                                                                                                                Filesize

                                                                                                                                                                216KB