Analysis

  • max time kernel
    135s
  • max time network
    153s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-20230220-en
  • resource tags

    arch:x64arch:x86image:win10v2004-20230220-enlocale:en-usos:windows10-2004-x64system
  • submitted
    03-06-2023 12:02

General

  • Target

    8dfa4cbcd189082d7f718b1db3622d5ccbd66abee2e4528137070b6acc777a21.exe

  • Size

    778KB

  • MD5

    f01b2a682e7633940397336966fef89c

  • SHA1

    dd194cab645ad0fa847b14748381e6b8fa2d99a4

  • SHA256

    8dfa4cbcd189082d7f718b1db3622d5ccbd66abee2e4528137070b6acc777a21

  • SHA512

    cc451b273660e41f9572f90430ba4efa14901202ef65a7466115abc9bc89f6b888a755a1fa35ba64a97e7f8247277ae1ae5488249a576a5bb546657bd53c70a5

  • SSDEEP

    12288:KMr7y90z7Np4wrxPKHM53KFrKpBsyUoIDCLmI06tWhj1DiAOe9G+:Zy2IErsyluI0Y41fOL+

Malware Config

Extracted

Family

redline

Botnet

dusa

C2

83.97.73.126:19046

Attributes
  • auth_value

    ee896466545fedf9de5406175fb82de5

Extracted

Family

redline

Botnet

brain

C2

83.97.73.126:19046

Attributes
  • auth_value

    5fb8269baadec0c49899b9a7a0c8851f

Signatures

  • Modifies Windows Defender Real-time Protection settings 3 TTPs 6 IoCs
  • RedLine

    RedLine Stealer is a malware family written in C#, first appearing in early 2020.

  • Checks computer location settings 2 TTPs 2 IoCs

    Looks up country code configured in the registry, likely geofence.

  • Executes dropped EXE 9 IoCs
  • Loads dropped DLL 1 IoCs
  • Reads user/profile data of web browsers 2 TTPs

    Infostealers often target stored browser data, which can include saved credentials etc.

  • Accesses cryptocurrency files/wallets, possible credential harvesting 2 TTPs
  • Adds Run key to start application 2 TTPs 6 IoCs
  • Checks installed software on the system 1 TTPs

    Looks up Uninstall key entries in the registry to enumerate software on the system.

  • Suspicious use of SetThreadContext 2 IoCs
  • Enumerates physical storage devices 1 TTPs

    Attempts to interact with connected storage/optical drive(s).

  • Program crash 1 IoCs
  • Creates scheduled task(s) 1 TTPs 1 IoCs

    Schtasks is often used by malware for persistence or to perform post-infection execution.

  • Suspicious behavior: EnumeratesProcesses 4 IoCs
  • Suspicious use of AdjustPrivilegeToken 2 IoCs
  • Suspicious use of FindShellTrayWindow 1 IoCs
  • Suspicious use of UnmapMainImage 1 IoCs
  • Suspicious use of WriteProcessMemory 58 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\8dfa4cbcd189082d7f718b1db3622d5ccbd66abee2e4528137070b6acc777a21.exe
    "C:\Users\Admin\AppData\Local\Temp\8dfa4cbcd189082d7f718b1db3622d5ccbd66abee2e4528137070b6acc777a21.exe"
    1⤵
    • Adds Run key to start application
    • Suspicious use of WriteProcessMemory
    PID:3832
    • C:\Users\Admin\AppData\Local\Temp\IXP000.TMP\y5308949.exe
      C:\Users\Admin\AppData\Local\Temp\IXP000.TMP\y5308949.exe
      2⤵
      • Executes dropped EXE
      • Adds Run key to start application
      • Suspicious use of WriteProcessMemory
      PID:4608
      • C:\Users\Admin\AppData\Local\Temp\IXP001.TMP\y0736444.exe
        C:\Users\Admin\AppData\Local\Temp\IXP001.TMP\y0736444.exe
        3⤵
        • Executes dropped EXE
        • Adds Run key to start application
        • Suspicious use of WriteProcessMemory
        PID:3376
        • C:\Users\Admin\AppData\Local\Temp\IXP002.TMP\k2430745.exe
          C:\Users\Admin\AppData\Local\Temp\IXP002.TMP\k2430745.exe
          4⤵
          • Executes dropped EXE
          • Suspicious use of SetThreadContext
          • Suspicious use of WriteProcessMemory
          PID:4664
          • C:\Windows\Microsoft.NET\Framework\v4.0.30319\AppLaunch.exe
            "C:\\Windows\\Microsoft.NET\\Framework\\v4.0.30319\\AppLaunch.exe"
            5⤵
            • Modifies Windows Defender Real-time Protection settings
            • Suspicious behavior: EnumeratesProcesses
            • Suspicious use of AdjustPrivilegeToken
            PID:1628
        • C:\Users\Admin\AppData\Local\Temp\IXP002.TMP\l9438839.exe
          C:\Users\Admin\AppData\Local\Temp\IXP002.TMP\l9438839.exe
          4⤵
          • Executes dropped EXE
          • Suspicious behavior: EnumeratesProcesses
          • Suspicious use of AdjustPrivilegeToken
          PID:232
      • C:\Users\Admin\AppData\Local\Temp\IXP001.TMP\m7711065.exe
        C:\Users\Admin\AppData\Local\Temp\IXP001.TMP\m7711065.exe
        3⤵
        • Checks computer location settings
        • Executes dropped EXE
        • Suspicious use of FindShellTrayWindow
        • Suspicious use of WriteProcessMemory
        PID:4968
        • C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe
          "C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe"
          4⤵
          • Checks computer location settings
          • Executes dropped EXE
          • Suspicious use of WriteProcessMemory
          PID:1508
          • C:\Windows\SysWOW64\schtasks.exe
            "C:\Windows\System32\schtasks.exe" /Create /SC MINUTE /MO 1 /TN metado.exe /TR "C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe" /F
            5⤵
            • Creates scheduled task(s)
            PID:4976
          • C:\Windows\SysWOW64\cmd.exe
            "C:\Windows\System32\cmd.exe" /k echo Y|CACLS "metado.exe" /P "Admin:N"&&CACLS "metado.exe" /P "Admin:R" /E&&echo Y|CACLS "..\a9e2a16078" /P "Admin:N"&&CACLS "..\a9e2a16078" /P "Admin:R" /E&&Exit
            5⤵
            • Suspicious use of WriteProcessMemory
            PID:3924
            • C:\Windows\SysWOW64\cmd.exe
              C:\Windows\system32\cmd.exe /S /D /c" echo Y"
              6⤵
                PID:4040
              • C:\Windows\SysWOW64\cacls.exe
                CACLS "metado.exe" /P "Admin:N"
                6⤵
                  PID:1488
                • C:\Windows\SysWOW64\cacls.exe
                  CACLS "metado.exe" /P "Admin:R" /E
                  6⤵
                    PID:2464
                  • C:\Windows\SysWOW64\cmd.exe
                    C:\Windows\system32\cmd.exe /S /D /c" echo Y"
                    6⤵
                      PID:796
                    • C:\Windows\SysWOW64\cacls.exe
                      CACLS "..\a9e2a16078" /P "Admin:N"
                      6⤵
                        PID:3932
                      • C:\Windows\SysWOW64\cacls.exe
                        CACLS "..\a9e2a16078" /P "Admin:R" /E
                        6⤵
                          PID:1608
                      • C:\Windows\SysWOW64\rundll32.exe
                        "C:\Windows\System32\rundll32.exe" C:\Users\Admin\AppData\Roaming\006700e5a2ab05\clip64.dll, Main
                        5⤵
                        • Loads dropped DLL
                        PID:4068
                • C:\Users\Admin\AppData\Local\Temp\IXP000.TMP\n7368013.exe
                  C:\Users\Admin\AppData\Local\Temp\IXP000.TMP\n7368013.exe
                  2⤵
                  • Executes dropped EXE
                  • Suspicious use of SetThreadContext
                  • Suspicious use of WriteProcessMemory
                  PID:2180
                  • C:\Windows\Microsoft.NET\Framework\v4.0.30319\AppLaunch.exe
                    "C:\\Windows\\Microsoft.NET\\Framework\\v4.0.30319\\AppLaunch.exe"
                    3⤵
                    • Suspicious use of UnmapMainImage
                    PID:3988
                    • C:\Windows\SysWOW64\WerFault.exe
                      C:\Windows\SysWOW64\WerFault.exe -u -p 3988 -s 12
                      4⤵
                      • Program crash
                      PID:4648
              • C:\Windows\SysWOW64\WerFault.exe
                C:\Windows\SysWOW64\WerFault.exe -pss -s 436 -p 3988 -ip 3988
                1⤵
                  PID:4136
                • C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe
                  C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe
                  1⤵
                  • Executes dropped EXE
                  PID:2152
                • C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe
                  C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe
                  1⤵
                  • Executes dropped EXE
                  PID:4256

                Network

                MITRE ATT&CK Enterprise v6

                Replay Monitor

                Loading Replay Monitor...

                Downloads

                • C:\Users\Admin\AppData\Local\Temp\IXP000.TMP\n7368013.exe

                  Filesize

                  304KB

                  MD5

                  6e88ad9b9fb72fa44c71f3706349d03c

                  SHA1

                  3bb4369b8e35604fd71064b9a9b17593de9e7aa3

                  SHA256

                  7534edf7564d41f37a52381e95c31d5c8f18c373f31e6d3e9448f66d9a88a622

                  SHA512

                  ff9252222ab8d43e33e43ea65092f48702d1b4c1b77612aa3f19b678d652a4cff9c1ebcf5e4ec2e9a7d796e99c284fd96d251f82332c4b27f3b80c7ddc59a0e5

                • C:\Users\Admin\AppData\Local\Temp\IXP000.TMP\n7368013.exe

                  Filesize

                  304KB

                  MD5

                  6e88ad9b9fb72fa44c71f3706349d03c

                  SHA1

                  3bb4369b8e35604fd71064b9a9b17593de9e7aa3

                  SHA256

                  7534edf7564d41f37a52381e95c31d5c8f18c373f31e6d3e9448f66d9a88a622

                  SHA512

                  ff9252222ab8d43e33e43ea65092f48702d1b4c1b77612aa3f19b678d652a4cff9c1ebcf5e4ec2e9a7d796e99c284fd96d251f82332c4b27f3b80c7ddc59a0e5

                • C:\Users\Admin\AppData\Local\Temp\IXP000.TMP\y5308949.exe

                  Filesize

                  448KB

                  MD5

                  1248ed885e081374ce2b77b0e9cccb7a

                  SHA1

                  12b3e90e91ac256e3d8ecaa5033ae07a1f648fe4

                  SHA256

                  63d67c188e0fccf0021ba02f1e11c0458b0e35a336b60d8fca52c05a309b4887

                  SHA512

                  381eedb26f7926ff020dacc4e0677ba22d2b0e69a105cae97056bc7c611d064210003b1d933afd1ec94be911cd1b6ba123324dd528f30ef87e74d32368f8eb23

                • C:\Users\Admin\AppData\Local\Temp\IXP000.TMP\y5308949.exe

                  Filesize

                  448KB

                  MD5

                  1248ed885e081374ce2b77b0e9cccb7a

                  SHA1

                  12b3e90e91ac256e3d8ecaa5033ae07a1f648fe4

                  SHA256

                  63d67c188e0fccf0021ba02f1e11c0458b0e35a336b60d8fca52c05a309b4887

                  SHA512

                  381eedb26f7926ff020dacc4e0677ba22d2b0e69a105cae97056bc7c611d064210003b1d933afd1ec94be911cd1b6ba123324dd528f30ef87e74d32368f8eb23

                • C:\Users\Admin\AppData\Local\Temp\IXP001.TMP\m7711065.exe

                  Filesize

                  216KB

                  MD5

                  4ea0234819c6857319a051520727f63d

                  SHA1

                  e2d96cd31bbc11f8eeee35b01845e874a523fdc7

                  SHA256

                  83f573adf0e3ad97b36994f3677dd67d9224899088d1f5f98cf77276e9b84cb0

                  SHA512

                  8b6f4de8c3b7d874f551a0641d4d7dfa7c5c0ebd0c1bf13aa1addffc0803e936d18eedc98e6e943c3677ca797259753cf570146e192c882877e2848507641bfe

                • C:\Users\Admin\AppData\Local\Temp\IXP001.TMP\m7711065.exe

                  Filesize

                  216KB

                  MD5

                  4ea0234819c6857319a051520727f63d

                  SHA1

                  e2d96cd31bbc11f8eeee35b01845e874a523fdc7

                  SHA256

                  83f573adf0e3ad97b36994f3677dd67d9224899088d1f5f98cf77276e9b84cb0

                  SHA512

                  8b6f4de8c3b7d874f551a0641d4d7dfa7c5c0ebd0c1bf13aa1addffc0803e936d18eedc98e6e943c3677ca797259753cf570146e192c882877e2848507641bfe

                • C:\Users\Admin\AppData\Local\Temp\IXP001.TMP\y0736444.exe

                  Filesize

                  276KB

                  MD5

                  c0f30a663f4f2314aeb8fdb8f45cfca1

                  SHA1

                  14676083229cb5ec439602d05f18ad0490720db9

                  SHA256

                  e91c26bea7289899567e2caebf0a6e2005317d0abd0626f4fb5a90252bfe09ee

                  SHA512

                  d98e011bb1dc4cd462641c836c5e03665bb1044fe3f6eceeb4b733e188c0953c3a56f6556ee7c308cf180fe12018947063c8ab495cb5362609fa1e094145d534

                • C:\Users\Admin\AppData\Local\Temp\IXP001.TMP\y0736444.exe

                  Filesize

                  276KB

                  MD5

                  c0f30a663f4f2314aeb8fdb8f45cfca1

                  SHA1

                  14676083229cb5ec439602d05f18ad0490720db9

                  SHA256

                  e91c26bea7289899567e2caebf0a6e2005317d0abd0626f4fb5a90252bfe09ee

                  SHA512

                  d98e011bb1dc4cd462641c836c5e03665bb1044fe3f6eceeb4b733e188c0953c3a56f6556ee7c308cf180fe12018947063c8ab495cb5362609fa1e094145d534

                • C:\Users\Admin\AppData\Local\Temp\IXP002.TMP\k2430745.exe

                  Filesize

                  147KB

                  MD5

                  08775293b7bdefa068e2058cd0bf1cbe

                  SHA1

                  79e5db7d14d73dc9767c53713edb59193014718e

                  SHA256

                  0a5637447a1339f2ab2868db2ed6a015a16be8960abc5776dc79c4c9f1ff694c

                  SHA512

                  f104038d71db38c0ecba790dd9145d182d234ce44c631c9314da63e30d42a7fe363d6e897bbc65a46dc466670fba88b5acfbce39b7865da08067ca672d063cbf

                • C:\Users\Admin\AppData\Local\Temp\IXP002.TMP\k2430745.exe

                  Filesize

                  147KB

                  MD5

                  08775293b7bdefa068e2058cd0bf1cbe

                  SHA1

                  79e5db7d14d73dc9767c53713edb59193014718e

                  SHA256

                  0a5637447a1339f2ab2868db2ed6a015a16be8960abc5776dc79c4c9f1ff694c

                  SHA512

                  f104038d71db38c0ecba790dd9145d182d234ce44c631c9314da63e30d42a7fe363d6e897bbc65a46dc466670fba88b5acfbce39b7865da08067ca672d063cbf

                • C:\Users\Admin\AppData\Local\Temp\IXP002.TMP\l9438839.exe

                  Filesize

                  168KB

                  MD5

                  1c8fa5a3555a64db06f2e034c1911b90

                  SHA1

                  ceb8e005df8885be32e6d7a5159bf0c4bb3d58c4

                  SHA256

                  995b8b73f0d6fb6bf75c9630b741afbdebbaaa4a1f159fe793684100571eda21

                  SHA512

                  69dd886c7ea5ef2553129de60d6d4e0a5e723576e230cd7895401fa6e91585af87db4b2ff86010e6d439034fe8d548501c0b4bf734d18dd8837b2e27d60b2def

                • C:\Users\Admin\AppData\Local\Temp\IXP002.TMP\l9438839.exe

                  Filesize

                  168KB

                  MD5

                  1c8fa5a3555a64db06f2e034c1911b90

                  SHA1

                  ceb8e005df8885be32e6d7a5159bf0c4bb3d58c4

                  SHA256

                  995b8b73f0d6fb6bf75c9630b741afbdebbaaa4a1f159fe793684100571eda21

                  SHA512

                  69dd886c7ea5ef2553129de60d6d4e0a5e723576e230cd7895401fa6e91585af87db4b2ff86010e6d439034fe8d548501c0b4bf734d18dd8837b2e27d60b2def

                • C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe

                  Filesize

                  216KB

                  MD5

                  4ea0234819c6857319a051520727f63d

                  SHA1

                  e2d96cd31bbc11f8eeee35b01845e874a523fdc7

                  SHA256

                  83f573adf0e3ad97b36994f3677dd67d9224899088d1f5f98cf77276e9b84cb0

                  SHA512

                  8b6f4de8c3b7d874f551a0641d4d7dfa7c5c0ebd0c1bf13aa1addffc0803e936d18eedc98e6e943c3677ca797259753cf570146e192c882877e2848507641bfe

                • C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe

                  Filesize

                  216KB

                  MD5

                  4ea0234819c6857319a051520727f63d

                  SHA1

                  e2d96cd31bbc11f8eeee35b01845e874a523fdc7

                  SHA256

                  83f573adf0e3ad97b36994f3677dd67d9224899088d1f5f98cf77276e9b84cb0

                  SHA512

                  8b6f4de8c3b7d874f551a0641d4d7dfa7c5c0ebd0c1bf13aa1addffc0803e936d18eedc98e6e943c3677ca797259753cf570146e192c882877e2848507641bfe

                • C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe

                  Filesize

                  216KB

                  MD5

                  4ea0234819c6857319a051520727f63d

                  SHA1

                  e2d96cd31bbc11f8eeee35b01845e874a523fdc7

                  SHA256

                  83f573adf0e3ad97b36994f3677dd67d9224899088d1f5f98cf77276e9b84cb0

                  SHA512

                  8b6f4de8c3b7d874f551a0641d4d7dfa7c5c0ebd0c1bf13aa1addffc0803e936d18eedc98e6e943c3677ca797259753cf570146e192c882877e2848507641bfe

                • C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe

                  Filesize

                  216KB

                  MD5

                  4ea0234819c6857319a051520727f63d

                  SHA1

                  e2d96cd31bbc11f8eeee35b01845e874a523fdc7

                  SHA256

                  83f573adf0e3ad97b36994f3677dd67d9224899088d1f5f98cf77276e9b84cb0

                  SHA512

                  8b6f4de8c3b7d874f551a0641d4d7dfa7c5c0ebd0c1bf13aa1addffc0803e936d18eedc98e6e943c3677ca797259753cf570146e192c882877e2848507641bfe

                • C:\Users\Admin\AppData\Local\Temp\a9e2a16078\metado.exe

                  Filesize

                  216KB

                  MD5

                  4ea0234819c6857319a051520727f63d

                  SHA1

                  e2d96cd31bbc11f8eeee35b01845e874a523fdc7

                  SHA256

                  83f573adf0e3ad97b36994f3677dd67d9224899088d1f5f98cf77276e9b84cb0

                  SHA512

                  8b6f4de8c3b7d874f551a0641d4d7dfa7c5c0ebd0c1bf13aa1addffc0803e936d18eedc98e6e943c3677ca797259753cf570146e192c882877e2848507641bfe

                • C:\Users\Admin\AppData\Roaming\006700e5a2ab05\clip64.dll

                  Filesize

                  89KB

                  MD5

                  547bae937be965d63f61d89e8eafb4a1

                  SHA1

                  85466c95625bcbb7f68aa89a367149d35f80e1fa

                  SHA256

                  015d60486e75035f83ea454e87afb38d11ec39643c33b07f61a40343078ee4f5

                  SHA512

                  1869b1cd3dcc09fbf9f965a8f45b647390e8859e6bf476293cbfd8b1122c660eca5db2943f0b1e77d451684fdef34ae503d5f357408e1a4fe5c1237871f5d02f

                • C:\Users\Admin\AppData\Roaming\006700e5a2ab05\clip64.dll

                  Filesize

                  89KB

                  MD5

                  547bae937be965d63f61d89e8eafb4a1

                  SHA1

                  85466c95625bcbb7f68aa89a367149d35f80e1fa

                  SHA256

                  015d60486e75035f83ea454e87afb38d11ec39643c33b07f61a40343078ee4f5

                  SHA512

                  1869b1cd3dcc09fbf9f965a8f45b647390e8859e6bf476293cbfd8b1122c660eca5db2943f0b1e77d451684fdef34ae503d5f357408e1a4fe5c1237871f5d02f

                • C:\Users\Admin\AppData\Roaming\006700e5a2ab05\clip64.dll

                  Filesize

                  89KB

                  MD5

                  547bae937be965d63f61d89e8eafb4a1

                  SHA1

                  85466c95625bcbb7f68aa89a367149d35f80e1fa

                  SHA256

                  015d60486e75035f83ea454e87afb38d11ec39643c33b07f61a40343078ee4f5

                  SHA512

                  1869b1cd3dcc09fbf9f965a8f45b647390e8859e6bf476293cbfd8b1122c660eca5db2943f0b1e77d451684fdef34ae503d5f357408e1a4fe5c1237871f5d02f

                • C:\Users\Admin\AppData\Roaming\006700e5a2ab05\cred64.dll

                  Filesize

                  162B

                  MD5

                  1b7c22a214949975556626d7217e9a39

                  SHA1

                  d01c97e2944166ed23e47e4a62ff471ab8fa031f

                  SHA256

                  340c8464c2007ce3f80682e15dfafa4180b641d53c14201b929906b7b0284d87

                  SHA512

                  ba64847cf1d4157d50abe4f4a1e5c1996fe387c5808e2f758c7fb3213bfefe1f3712d343f0c30a16819749840954654a70611d2250fd0f7b032429db7afd2cc5

                • memory/232-162-0x00000000005D0000-0x00000000005FE000-memory.dmp

                  Filesize

                  184KB

                • memory/232-165-0x000000000A340000-0x000000000A352000-memory.dmp

                  Filesize

                  72KB

                • memory/232-175-0x000000000BD40000-0x000000000BF02000-memory.dmp

                  Filesize

                  1.8MB

                • memory/232-174-0x0000000004E00000-0x0000000004E10000-memory.dmp

                  Filesize

                  64KB

                • memory/232-172-0x000000000B520000-0x000000000B570000-memory.dmp

                  Filesize

                  320KB

                • memory/232-171-0x000000000AED0000-0x000000000AF36000-memory.dmp

                  Filesize

                  408KB

                • memory/232-170-0x000000000B5C0000-0x000000000BB64000-memory.dmp

                  Filesize

                  5.6MB

                • memory/232-169-0x000000000AF70000-0x000000000B002000-memory.dmp

                  Filesize

                  584KB

                • memory/232-168-0x000000000A7B0000-0x000000000A826000-memory.dmp

                  Filesize

                  472KB

                • memory/232-163-0x000000000A8B0000-0x000000000AEC8000-memory.dmp

                  Filesize

                  6.1MB

                • memory/232-164-0x000000000A410000-0x000000000A51A000-memory.dmp

                  Filesize

                  1.0MB

                • memory/232-167-0x0000000004E00000-0x0000000004E10000-memory.dmp

                  Filesize

                  64KB

                • memory/232-166-0x000000000A3A0000-0x000000000A3DC000-memory.dmp

                  Filesize

                  240KB

                • memory/232-176-0x000000000C440000-0x000000000C96C000-memory.dmp

                  Filesize

                  5.2MB

                • memory/1628-154-0x0000000000400000-0x000000000040A000-memory.dmp

                  Filesize

                  40KB

                • memory/3988-194-0x00000000005B0000-0x00000000005DE000-memory.dmp

                  Filesize

                  184KB