Analysis

  • max time kernel
    190s
  • max time network
    192s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-20220721-en
  • resource tags

    arch:x64arch:x86image:win10v2004-20220721-enlocale:en-usos:windows10-2004-x64system
  • submitted
    01-08-2022 05:32

General

  • Target

    5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22.exe

  • Size

    360KB

  • MD5

    85315030e7efbe46eb1318d0bd0a558e

  • SHA1

    1ed6de7ca6f0ab330bba35c15301ae0dc5338234

  • SHA256

    5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22

  • SHA512

    6c76e8bff6906c4dea42640849a347161a9d53f6a4ff40efd08aa06a5d2e53b762bdb710e4f53f94025345db2ddceec8f028354a1581774f44a0afd11a553958

Malware Config

Extracted

Path

C:\$Recycle.Bin\S-1-5-21-2372564722-193526734-2636556182-1000\_ReCoVeRy_+rasie.txt

Family

teslacrypt

Ransom Note
NOT YOUR LANGUAGE? USE https://translate.google.com What happened to your files ? All of your files were protected by a strong encryption with RSA4096 More information about the encryption keys using RSA4096 can be found here: http://en.wikipedia.org/wiki/RSA_(cryptosystem) How did this happen ? !!! Specially for your PC was generated personal RSA4096 Key , both public and private. !!! ALL YOUR FILES were encrypted with the public key, which has been transferred to your computer via the Internet. !!! Decrypting of your files is only possible with the help of the private key and decrypt program , which is on our Secret Server What do I do ? So, there are two ways you can choose: wait for a miracle and get your price doubled, or start obtaining BITCOIN NOW! , and restore your data easy way. If You have really valuable data, you better not waste your time, because there is no other way to get your files, except make a payment. For more specific instructions, please visit your personal home page, there are a few different addresses pointing to your page below: 1 - http://sondr5344ygfweyjbfkw4fhsefv.heliofetch.at/75F386CCBD38A41 2 - http://pts764gt354fder34fsqw45gdfsavadfgsfg.kraskula.com/75F386CCBD38A41 3 - http://yyre45dbvn2nhbefbmh.begumvelic.at/75F386CCBD38A41 If for some reasons the addresses are not available, follow these steps: 1 - Download and install tor-browser: http://www.torproject.org/projects/torbrowser.html.en 2 - After a successful installation, run the browser 3 - Type in the address bar: xlowfznrg4wf7dli.onion/75F386CCBD38A41 4 - Follow the instructions on the site IMPORTANT INFORMATION Your personal pages http://sondr5344ygfweyjbfkw4fhsefv.heliofetch.at/75F386CCBD38A41 http://pts764gt354fder34fsqw45gdfsavadfgsfg.kraskula.com/75F386CCBD38A41 http://yyre45dbvn2nhbefbmh.begumvelic.at/75F386CCBD38A41 Your personal page Tor-Browser xlowfznrg4wf7dli.ONION/75F386CCBD38A41
URLs

http://sondr5344ygfweyjbfkw4fhsefv.heliofetch.at/75F386CCBD38A41

http://pts764gt354fder34fsqw45gdfsavadfgsfg.kraskula.com/75F386CCBD38A41

http://yyre45dbvn2nhbefbmh.begumvelic.at/75F386CCBD38A41

http://xlowfznrg4wf7dli.ONION/75F386CCBD38A41

Extracted

Path

C:\$Recycle.Bin\S-1-5-21-2372564722-193526734-2636556182-1000\_ReCoVeRy_+rasie.html

Ransom Note
<html> <style>a { color:green; }.tb { background:white; border-style:solid; border-width:1px; padding:3px; border-color:lime; } .ttl { font-size:13px; color:880000; }</style><body style="background:#33CCFF;"> <center> <div style="text-align:left; font-family:Arial; <!---4231213423142134231421342341234 --> font-size:13px; line-height:20px; margin-top:10px; width:800px; background:#F4F4F4; padding:20px; border-style:solid; border-width:5px; border-color:#BABABA;"> <b><font class="ttl"><center><b>NOT YOUR LANGUAGE? USE <a href="https://translate.google.com" target="_blank">Google Translate</a></b></center> What<!------4231213423142134231421342341234 --> happened <!------4231213423142134231421342341234 --> to your<!------4231213423142134231421342341234 --> files?</b></font><br> <font style="font-size:13px;">All <!------4231213423142134231421342341234 -->of your files<!------4231213423142134231421342341234 --> were <!------4231213423142134231421342341234 --> protected by a strong<!------4231213423142134231421342341234 --> encr<!---4231213423142134231421342341234 -->yption wi<!---4231213423142134231421342341234 -->th <!------4231213423142134231421342341234 -->RSA4096 <!------4231213423142134231421342341234 --> <br> More <!------4231213423142134231421342341234 --> information about the <!------4231213423142134231421342341234 -->encryption RSA4096 can be<!------4231213423142134231421342341234 --> fou<!---4231213423142134231421342341234 -->nd <a href= http://en.wikipedia.org/wiki/RSA_(cryptosystem) target="_blank"> htt<!--4231213423142134231421342341234 -->ps:<!--4231213423142134231421342341234 -->//en<!--4231213423142134231421342341234 -->.w<!--4231213423142134231421342341234 -->ikipedia<!--4231213423142134231421342341234 -->.<!--4231213423142134231421342341234 -->org/wiki/RSA_(cry<!--4231213423142134231421342341234 -->ptosystem) </a><br></font> <br><b><font class="ttl">Wh<!--4231213423142134231421342341234 -->at <!------4231213423142134231421342341234 --> does th<!--4231213423142134231421342341234 -->is mean?</b></font><br><font style="font-size:13px;"> T<!--4231213423142134231421342341234 -->his<!------4231213423142134231421342341234 --> mea<!--4231213423142134231421342341234 -->ns that the <!------4231213423142134231421342341234 --> str<!--4231213423142134231421342341234 -->ucture and da<!--4231213423142134231421342341234 -->ta wi<!--4231213423142134231421342341234 -->thin your <!------4231213423142134231421342341234 -->files ha<!--4231213423142134231421342341234 -->ve be<!--4231213423142134231421342341234 -->en<!------4231213423142134231421342341234 --> irre<!--4231213423142134231421342341234 -->voca<!--4231213423142134231421342341234 -->bly changed, you will not be able work wi<!--4231213423142134231421342341234 -->th them, read<!------4231213423142134231421342341234 --> th<!--4231213423142134231421342341234 -->em or see them, <!------4231213423142134231421342341234 -->it is the s<!--4231213423142134231421342341234 -->ame thing <!------4231213423142134231421342341234 -->as los<!--4231213423142134231421342341234 -->ing <!------4231213423142134231421342341234 -->them for<!--4231213423142134231421342341234 -->ever, but with our he<!--4231213423142134231421342341234 -->lp, you <!------4231213423142134231421342341234 --> can re<!--4231213423142134231421342341234 -->st<!--4231213423142134231421342341234 -->ore t<!--4231213423142134231421342341234 -->hem <br><br><b><font class="ttl"><!------4231213423142134231421342341234 -->Ho<!--4231213423142134231421342341234 -->w d<!--4231213423142134231421342341234 -->id th<!--4231213423142134231421342341234 -->is hap<!--4231213423142134231421342341234 -->pen?<!------4231213423142134231421342341234 --></b></font> <br> <!------4231213423142134231421342341234 --> <font style="font-size:13px;"><!------4231213423142134231421342341234 --> Espec<!--4231213423142134231421342341234 -->ially for y<!--4231213423142134231421342341234 -->ou,<!------4231213423142134231421342341234 --> on our SER<!--4231213423142134231421342341234 -->VER <!------4231213423142134231421342341234 -->was gene<!--4231213423142134231421342341234 -->rated <!------4231213423142134231421342341234 -->the sec<!--4231213423142134231421342341234 -->ret k<!--4231213423142134231421342341234 -->ey <br>Al<!--4231213423142134231421342341234-->l y<!--4231213423142134231421342341234-->our <!------4231213423142134231421342341234 --> files w<!--4231213423142134231421342341234-->ere encry<!--4231213423142134231421342341234-->pted with the p<!--4231213423142134231421342341234-->ublic k<!--4231213423142134231421342341234-->ey, <!------4231213423142134231421342341234 --> wh<!--4231213423142134231421342341234-->ich has b<!--4231213423142134231421342341234-->een <!------4231213423142134231421342341234 --> trans<!--4231213423142134231421342341234-->ferred to <!------4231213423142134231421342341234 -->y<!--4231213423142134231421342341234-->our co<!--4231213423142134231421342341234-->mputer via <!------4231213423142134231421342341234 -->the Inter<!--4231213423142134231421342341234-->net.<!--4231213423142134231421342341234--><br> <!------4231213423142134231421342341234 --> Decr<!--4231213423142134231421342341234-->ypting of <!------4231213423142134231421342341234 -->YO<!--4231213423142134231421342341234-->UR FI<!--4231213423142134231421342341234-->LES is <!--4231213423142134231421342341234 -->on<!--4231213423142134231421342341234 -->ly p<!--4231213423142134231421342341234 -->oss<!--4231213423142134231421342341234-->ible <!--- -4231213423142134231421342341234 -->w<!--4231213423142134231421342341234 -->ith the he<!--4231213423142134231421342341234-->lp of t<!--4231213423142134231421342341234 -->he <!----4231213423142134231421342341234 -->pri<!--4231213423142134231421342341234-->va<!--4231213423142134231421342341234 -->te k<!--4231213423142134231421342341234-->ey a<!--4231213423142134231421342341234 -->nd <!--4231213423142134231421342341234 -->d<!--4231213423142134231421342341234 -->ecr<!--4231213423142134231421342341234-->ypt p<!--4231213423142134231421342341234 -->rog<!--4231213423142134231421342341234-->ram <!--4231213423142134231421342341234 -->wh<!--4231213423142134231421342341234-->ich is on our <!--- -4231213423142134231421342341234 -->Sec<!--4231213423142134231421342341234-->ret <!--4231213423142134231421342341234 -->Ser<!--4231213423142134231421342341234-->ver!!! </font><br><br><b><font class="ttl">Wh<!--4231213423142134231421342341234-->at do I do?</b></font> <br><font style="font-size:13px;">Alas, if you <!--4231213423142134231421342341234 --> do not take <!---4231213423142134231421342341234 --> the nece<!--4231213423142134231421342341234-->ssary meas<!--4231213423142134231421342341234-->ures <!--4231213423142134231421342341234-->for the spec<!--4231213423142134231421342341234-->ified ti<!--4231213423142134231421342341234-->me th<!--4231213423142134231421342341234-->en t<!--4231213423142134231421342341234-->he co<!--4231213423142134231421342341234-->nditions fo<!--4231213423142134231421342341234-->r obta<!--4231213423142134231421342341234-->ining the priv<!--4231213423142134231421342341234-->ate ke<!--4231213423142134231421342341234-->y w<!--4231213423142134231421342341234-->ill be cha<!--4231213423142134231421342341234-->nged<!--- 4231213423142134231421342341234 --> <br> <!-----4231213423142134231421342341234 --> If you really need <!------4231213423142134231421342341234 --> your data, <!------4231213423142134231421342341234 -->then we suggest you <!------4231213423142134231421342341234 --> do not waste<!------4231213423142134231421342341234 --> valuable <!------4231213423142134231421342341234 --> time searching <!------4231213423142134231421342341234 -->for other <!------4231213423142134231421342341234 --> solutions <!------4231213423142134231421342341234 -->becausen <!----4231213423142134231421342341234 --> they do not exist.</font><br><br> <!----4231213423142134231421342341234 --><div class="tb" style="color:#880000; font-size:13px; border-width:3px;">For more specific instructions, please<!------4231213423142134231421342341234 --> visit your <!------4231213423142134231421342341234 --> personal <!------4231213423142134231421342341234 -->home page,<!------4231213423142134231421342341234 --> there are<!------4231213423142134231421342341234 --> a few <!------4231213423142134231421342341234 -->different <!------4231213423142134231421342341234 -->addresses<!------4231213423142134231421342341234 --> pointing to <!------4231213423142134231421342341234 --> your page<!------4231213423142134231421342341234 --> below:<b><hr> <!---000==-=-==-=-=-=-=-=-=---> 1 - <a href=http://sondr5344ygfweyjbfkw4fhsefv.heliofetch.at/75F386CCBD38A41 target="_blank">http://sondr5344ygfweyjbfkw4fhsefv.heliofetch.at/75F386CCBD38A41</a> <br> <!------000==-=-==-=-=-=-=-=-= --> 2 - <a href=http://pts764gt354fder34fsqw45gdfsavadfgsfg.kraskula.com/75F386CCBD38A41 target="_blank">http://pts764gt354fder34fsqw45gdfsavadfgsfg.kraskula.com/75F386CCBD38A41</a> <br> <!------000==-=-==-=-=-=-=-=-= --> 3 - <a href=http://yyre45dbvn2nhbefbmh.begumvelic.at/75F386CCBD38A41 target="_blank">http://yyre45dbvn2nhbefbmh.begumvelic.at/75F386CCBD38A41</a> <br> <!------000==-=-==-=-=-=-=-=-= --></div><br><div class="tb" style="font-size:13px; border-color:#880000;"><b>If for some reasons the <!-----000==-=-==-=-=-=-=-=-= --> addresses are not available, <!------000==-=-==-=-=-=-=-=-= --> follow these steps:</b> <hr> 1 - <!------000==-=-==-=-=-=-=-=-= --> Download and <!------000==-=-==-=-=-=-=-=-= --> install tor-browser: <a href=http://www.torproject.org/projects/torbrowser.html.en target="_blank">http://www.torproject.org/projects/torbrowser.html.en</a><br> 2 - <!---000==-=-==-=-=-=-=-=-= --> Af<!---000==-=-==-=-=-=-=-=-=--->ter a<!---000==-=-==-=-=-=-=-=-=---> succe<!---000==-=-==-=-=-=-=-=-=--->ssful<!------000==-=-==-=-=-=-=-=-= --> instal<!---000==-=-==-=-=-=-=-=-=--->lation, run the br<!---000==-=-==-=-=-=-=-=-=--->owser and w<!---000==-=-==-=-=-=-=-=-=--->ait for initi<!---000==-=-==-=-=-=-=-=-=--->alization.<br> 3 - <!--- 000==-=-==-=-=-=-=-=-= --> Ty<!---000==-=-==-=-=-=-=-=-=--->pe<!-- 000==-=-==-=-=-=-=-=-= --> in<!-- 000==-=-==-=-=-=-=-=-= --> the t<!---000==-=-==-=-=-=-=-=-=--->or-bro<!---000==-=-==-=-=-=-=-=-=--->wser<!-- 000==-=-==-=-=-=-=-=-= --> add<!---000==-=-==-=-=-=-=-=-=--->ress<!-- 000==-=-==-=-=-=-=-=-= --> bar: <font style="font-weight:bold; color:#009977;"><!-- 000==-=-==-=-=-=-=-=-= -->xlowfznrg4wf7dli.onion/75F386CCBD38A41<!-- 000==-=-==-=-=-=-=-=-= --></font><!-- 000==-=-==-=-=-=-=-=-= --><br> 4 - <!--- 000==-=-==-=-=-=-=-=-= --> Fol<!---000==-=-==-=-=-=-=-=-=--->low the instr<!---000==-=-==-=-=-=-=-=-=--->uctions <!-- 000==-=-==-=-=-=-=-=-= --> on the site.</div><br><br><b>!!! IMPO<!---000==-=-==-=-=-=-=-=-=--->RTANT INFO<!---000==-=-==-=-=-=-=-=-=--->RMATION:</b><br> <!-----000==-=-==-=-=-=-=-=-= --><div class="tb" style="width:790px;"><!-----000==-=-==-=-=-=-=-=-= --> Yo<!---000==-=-==-=-=-=-=-=-=--->ur Pers<!---000==-=-==-=-=-=-=-=-=--->onal PAGES<b>: <br> <a href=http://sondr5344ygfweyjbfkw4fhsefv.heliofetch.at/75F386CCBD38A41 target="_blank">http://sondr5344ygfweyjbfkw4fhsefv.heliofetch.at/75F386CCBD38A41</a> <br><a href=http://pts764gt354fder34fsqw45gdfsavadfgsfg.kraskula.com/75F386CCBD38A41 target="_blank">http://pts764gt354fder34fsqw45gdfsavadfgsfg.kraskula.com/75F386CCBD38A41</a> <br> <!-----000==-=-==-=-=-=-=-=-= --><a href=http://yyre45dbvn2nhbefbmh.begumvelic.at/75F386CCBD38A41 target="_blank">http://yyre45dbvn2nhbefbmh.begumvelic.at/75F386CCBD38A41</a> <br> <!-----000==-=-==-=-=-=-=-=-= --> Your <!------000==-=-==-=-=-=-=-=-= --> Personal TOR-Browser<!-----000==-=-==-=-=-=-=-=-= --> page : <!-----000==-=-==-=-=-=-=-=-= --><font style="font-weight:bold; color:#009977;"><!-- 000==-=-==-=-=-=-=-=-= -->xlowfznrg4wf7dli.onion/75F386CCBD38A41<!-- 000==-=-==-=-=-=-=-=-= --></font><br> <!-----000==-=-==-=-=-=-=-=-= --> Your personal <!------000==-=-==-=-=-=-=-=-= --> ID <!-----000==-=-==-=-=-=-=-=-= --> (if you open <!------000==-=-==-=-=-=-=-=-= --> the site directly): <!-----000==-=-==-=-=-=-=-=-= --> <font style="font-weight:bold; color:#770000;">75F386CCBD38A41</font><br> </div></div></center></body></html>

Signatures

  • TeslaCrypt, AlphaCrypt

    Ransomware based on CryptoLocker. Shut down by the developers in 2016.

  • Deletes shadow copies 2 TTPs

    Ransomware often targets backup files to inhibit system recovery.

  • Executes dropped EXE 2 IoCs
  • Checks computer location settings 2 TTPs 2 IoCs

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

  • Adds Run key to start application 2 TTPs 2 IoCs
  • Suspicious use of SetThreadContext 2 IoCs
  • Drops file in Program Files directory 64 IoCs
  • Drops file in Windows directory 2 IoCs
  • Enumerates physical storage devices 1 TTPs

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

  • Suspicious behavior: EnumeratesProcesses 64 IoCs
  • Suspicious use of AdjustPrivilegeToken 47 IoCs
  • Suspicious use of WriteProcessMemory 28 IoCs
  • System policy modification 1 TTPs 2 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22.exe
    "C:\Users\Admin\AppData\Local\Temp\5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22.exe"
    1⤵
    • Suspicious use of SetThreadContext
    • Suspicious use of WriteProcessMemory
    PID:3308
    • C:\Users\Admin\AppData\Local\Temp\5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22.exe
      "C:\Users\Admin\AppData\Local\Temp\5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22.exe"
      2⤵
      • Checks computer location settings
      • Drops file in Windows directory
      • Suspicious use of AdjustPrivilegeToken
      • Suspicious use of WriteProcessMemory
      PID:1132
      • C:\Windows\mxrmywehjhmg.exe
        C:\Windows\mxrmywehjhmg.exe
        3⤵
        • Executes dropped EXE
        • Suspicious use of SetThreadContext
        • Suspicious use of WriteProcessMemory
        PID:4296
        • C:\Windows\mxrmywehjhmg.exe
          C:\Windows\mxrmywehjhmg.exe
          4⤵
          • Executes dropped EXE
          • Checks computer location settings
          • Adds Run key to start application
          • Drops file in Program Files directory
          • Suspicious behavior: EnumeratesProcesses
          • Suspicious use of AdjustPrivilegeToken
          • Suspicious use of WriteProcessMemory
          • System policy modification
          PID:4724
          • C:\Windows\System32\wbem\WMIC.exe
            "C:\Windows\System32\wbem\WMIC.exe" shadowcopy delete /nointeractive
            5⤵
            • Suspicious use of AdjustPrivilegeToken
            PID:4692
      • C:\Windows\SysWOW64\cmd.exe
        "C:\Windows\system32\cmd.exe" /c DEL C:\Users\Admin\AppData\Local\Temp\5CB5F1~1.EXE
        3⤵
          PID:740
    • C:\Windows\system32\vssvc.exe
      C:\Windows\system32\vssvc.exe
      1⤵
      • Suspicious use of AdjustPrivilegeToken
      PID:5064

    Network

    MITRE ATT&CK Enterprise v6

    Replay Monitor

    Loading Replay Monitor...

    Downloads

    • C:\Windows\mxrmywehjhmg.exe

      Filesize

      360KB

      MD5

      85315030e7efbe46eb1318d0bd0a558e

      SHA1

      1ed6de7ca6f0ab330bba35c15301ae0dc5338234

      SHA256

      5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22

      SHA512

      6c76e8bff6906c4dea42640849a347161a9d53f6a4ff40efd08aa06a5d2e53b762bdb710e4f53f94025345db2ddceec8f028354a1581774f44a0afd11a553958

    • C:\Windows\mxrmywehjhmg.exe

      Filesize

      360KB

      MD5

      85315030e7efbe46eb1318d0bd0a558e

      SHA1

      1ed6de7ca6f0ab330bba35c15301ae0dc5338234

      SHA256

      5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22

      SHA512

      6c76e8bff6906c4dea42640849a347161a9d53f6a4ff40efd08aa06a5d2e53b762bdb710e4f53f94025345db2ddceec8f028354a1581774f44a0afd11a553958

    • C:\Windows\mxrmywehjhmg.exe

      Filesize

      360KB

      MD5

      85315030e7efbe46eb1318d0bd0a558e

      SHA1

      1ed6de7ca6f0ab330bba35c15301ae0dc5338234

      SHA256

      5cb5f13c24b9631c14ddb4fe893ff4fad3da3dda8cf353013d4a5ddf09d08f22

      SHA512

      6c76e8bff6906c4dea42640849a347161a9d53f6a4ff40efd08aa06a5d2e53b762bdb710e4f53f94025345db2ddceec8f028354a1581774f44a0afd11a553958

    • memory/740-142-0x0000000000000000-mapping.dmp

    • memory/1132-141-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/1132-133-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/1132-134-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/1132-137-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/1132-143-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/1132-132-0x0000000000000000-mapping.dmp

    • memory/1132-136-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/3308-131-0x0000000000720000-0x0000000000724000-memory.dmp

      Filesize

      16KB

    • memory/3308-130-0x0000000000720000-0x0000000000724000-memory.dmp

      Filesize

      16KB

    • memory/3308-135-0x0000000000720000-0x0000000000724000-memory.dmp

      Filesize

      16KB

    • memory/4296-138-0x0000000000000000-mapping.dmp

    • memory/4692-150-0x0000000000000000-mapping.dmp

    • memory/4724-144-0x0000000000000000-mapping.dmp

    • memory/4724-147-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/4724-148-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/4724-149-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB

    • memory/4724-151-0x0000000000400000-0x0000000000486000-memory.dmp

      Filesize

      536KB