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Evidence of Stronger Ties Between North Korea and SWIFT Banking Attacks
Aaron Shelmire
May 27, 2016
<p><strong>Five new additional pieces of malware code discovered that contain unique portions of code related to the the SWIFT attacks.</strong></p><p>Recently, malware <a href="http://www.symantec.com/connect/blogs/swift-attackers-malware-linked-more-financial-attacks" target="_blank">analysts at Symantec</a> discovered two subroutines that were shared amongst North Korea’s Lazarus’ groups Operation Blockbuster malware and two samples of malware from the recent SWIFT attacks.</p><p>The shared subroutines are displayed as evidence to relate the SWIFT intrusion activity to the Lazarus group. Symantec’s analysis was utilized in the <a href="http://www.nytimes.com/2016/05/27/business/dealbook/north-korea-linked-to-digital-thefts-from-global-banks.html?_r=0" target="_blank">The New York Times story</a> on May 27, 2016. Their findings supported a claim that these were the only two pieces of software with this shared code.</p><p>The Anomali Labs team has conducted deeper research into a very large malware data repository. This process utilized the yara signature below to search for the shared subroutines. At first, we believed it would produce a lot of false positives. Instead, this search not only failed to result in any false positives, but also turned up five other pieces of malware which share this code. We see this as a possible attribution of the Lazarus group attacks to other attacks that involved these same five pieces of malware code.</p><table border="1" width="100%"><tbody><tr><td style="width: 86px; text-align: center; vertical-align: top;" width="86">Malware Family</td><td style="width: 86px; text-align: center; vertical-align: top;" width="160">Md5 hash</td><td style="width: 86px; text-align: center; vertical-align: top;" width="221">Notes</td></tr><tr><td style="width: 86px; text-align: center; vertical-align: top;" width="86">SWIFT BanSwift</td><td style="width: 86px; text-align: center; vertical-align: top;" width="160">5d0ffbc8389f27b0649696f0ef5b3cfe</td><td style="width: 86px; text-align: center; vertical-align: top;" width="221">evchk.bat dropper</td></tr><tr><td style="width: 86px; text-align: center; vertical-align: top;" width="86">SWIFT Fake Foxit Reader</td><td style="width: 86px; text-align: center; vertical-align: top;" width="160">0b9bf941e2539eaa34756a9e2c0d5343</td><td style="width: 86px; text-align: center; vertical-align: top;" width="221">A Fake Foxit Reader submitted to Virustotal from Vietnam in December 2015 (similar sample detailed at <a href="https://blogs.mcafee.com/mcafee-labs/attacks-swift-banking-system-benefit-insider-knowledge/" target="_blank">https://blogs.mcafee.com/mcafee-labs/attacks-swift-banking-system-benefit-insider-knowledge/</a>)</td></tr><tr><td style="width: 86px; text-align: center; vertical-align: top;" width="86">SMBWorm</td><td style="width: 86px; text-align: center; vertical-align: top;" width="160">558b020ce2c80710605ed30678b6fd0c</td><td style="width: 86px; text-align: center; vertical-align: top;" width="221">Known North Korean Malware</td></tr><tr><td style="width: 86px; text-align: center; vertical-align: top;" width="86">Memory dump with SMBWorm</td><td style="width: 86px; text-align: center; vertical-align: top;" width="160">96f4e767aa6bb1a1a5ab22e0662eec86</td><td style="width: 86px; text-align: center; vertical-align: top;" width="221"> </td></tr><tr><td style="width: 86px; text-align: center; vertical-align: top;" width="86">Unknown “hkcmd” tool</td><td style="width: 86px; text-align: center; vertical-align: top;" width="160">b0ec717aeece8d5d865a4f7481e941c5</td><td style="width: 86px; text-align: center; vertical-align: top;" width="221">1st Submitted from Canada, likely from an AV organization. 2016/04/22. PE Build Date of December 2010.</td></tr><tr><td style="width: 86px; text-align: center; vertical-align: top;" width="86">imkrmig.exe</td><td style="width: 86px; text-align: center; vertical-align: top;" width="160">5a85ea837323554a0578f78f4e7febd8</td><td style="width: 86px; text-align: center; vertical-align: top;" width="221">An unknown backdoor posing as a Korean sample of Microsoft Office 2007.</td></tr></tbody></table><p><em>Table 1. Malware families and samples known to include the Lazarus Wipe File routine.</em></p><p>Our approach to code comparison was to utilize Position Independent Code function hashes to compare the samples against one another. This process utilizes cryptographic hash values derived from the instruction mnemonics within the binary code. By performing this comparison, we can see the direct overlap of these shared functions between the various samples.</p><p><img alt="" sizes="(max-width: 860px) 100vw, 860px" src="https://cdn.filestackcontent.com/anyIXkP7Q8SjarJVp53d" srcset="https://blog.anomali.com/hs-fs/hubfs/Picture50.png?t=1478873412701&width=430&height=69&name=Picture50.png 430w, https://blog.anomali.com/hs-fs/hubfs/Picture50.png?t=1478873412701&width=860&height=138&name=Picture50.png 860w, https://blog.anomali.com/hs-fs/hubfs/Picture50.png?t=1478873412701&width=1290&height=207&name=Picture50.png 1290w, https://blog.anomali.com/hs-fs/hubfs/Picture50.png?t=1478873412701&width=1720&height=276&name=Picture50.png 1720w, https://blog.anomali.com/hs-fs/hubfs/Picture50.png?t=1478873412701&width=2150&height=345&name=Picture50.png 2150w, https://blog.anomali.com/hs-fs/hubfs/Picture50.png?t=1478873412701&width=2580&height=414&name=Picture50.png 2580w" style="display: block; margin-left: auto; margin-right: auto;" title="Picture50.png"/></p><p><em>Figure 1: The function overlap viewed from ae086350239380f56470c19d6a200f7d251c7422c7bc5ce74730ee8bab8e6283 as veiwed within IDAPro</em></p><p><em><em>Additionally, there are other function hashes (seven) that are shared amongst the Trojan.Filmis and various SWIFT-related malware samples. Anomali LABS is unsure of how rare these functions are at this point.</em></em></p><p><em><em><strong>Investigative Process</strong></em></em></p><p><em><em>We began by taking a look at the two subroutines that are reported to be unique by Symantec. We retrieved the API names and added those to a yara signature. In some cases, the APIs are MoveFileExA instead of MoveFileEx.</em></em></p><p><em><em>We then took a look at the code used. There is a small portion of code where a file name consisting of randomly generated lowercase letters is created. This was used as part of the criteria.</em></em></p><p><em><em>Using this criteria, we began a search of a large malware database starting on Thursday night. On Friday morning, we thought we’d be faced with a sea of false positives. But it only returned 10 matches! Four of those were known samples of the SWIFT malware, and one sample was a zip file that includes a known SWIFT sample. The other five samples are detailed above.</em></em></p><p><em><em><strong>Appendix</strong></em></em></p><p><em><em>Additional Samples related to the SWIFT intrusions (ref: <a href="http://baesystemsai.blogspot.com/2016/04/two-bytes-to-951m.html" target="_blank">http://baesystemsai.blogspot.com/2016/04/two-bytes-to-951m.html</a>)</em></em></p><table border="1" width="100%"><tbody><tr><td style="width: 74px; text-align: center; vertical-align: top;" width="74"><em><em><strong>Filename</strong> </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="287"><em><em><strong>md5</strong> </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="107"><em><em><strong>AntiVirus Name</strong> </em></em></td></tr><tr><td style="width: 74px; text-align: center; vertical-align: top;" width="74"><em><em>evtsys.exe </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="287"><em><em>5d0ffbc8389f27b0649696f0ef5b3cfe </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="107"><em><em>BanSwift </em></em></td></tr><tr><td style="width: 74px; text-align: center; vertical-align: top;" width="74"><em><em>evtdiag.exe </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="287"><em><em>24d76abbc0a10e4c977a28b33c879248 </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="107"><em><em>BanSwift </em></em></td></tr><tr><td style="width: 74px; text-align: center; vertical-align: top;" width="74"><em><em>nroff_b.exe </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="287"><em><em>1d0e79feb6d7ed23eb1bf7f257ce4fee </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="107"><em><em>BanSwift </em></em></td></tr><tr><td style="width: 74px; text-align: center; vertical-align: top;" width="74"><em><em>gpca.dat </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="287"><em><em>f7272bb1374bf3af193ea1d1845b27fd </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="107"><em><em> </em></em></td></tr><tr><td style="width: 74px; text-align: center; vertical-align: top;" width="74"><em><em>mspdclr.exe </em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="287"><em><em>909e1b840909522fe6ba3d4dfd197d93</em></em></td><td style="width: 74px; text-align: center; vertical-align: top;" width="107"><em><em>BanSwift </em></em></td></tr></tbody></table><p><em><em>Other previously known Lazarus Group samples:</em></em></p><p><em><em>138464214c78a73e3714d784697745acbf692ef40419d31418e4018e752cb92b<br/> bdcfa3b6ca6b351e76241bca17e8f30cc8f35bed0309cee91966be9bd01cb848<br/> ddebee8fe97252203e6c943fb4f9b37ade3d5fefe90edba7a37e4856056f8cd6<br/> 4d4b17ddbcf4ce397f76cf0a2e230c9d513b23065f746a5ee2de74f447be39b9<br/> e2ecec43da974db02f624ecadc94baf1d21fd1a5c4990c15863bb9929f781a0a<br/> eff542ac8e37db48821cb4e5a7d95c044fff27557763de3a891b40ebeb52cc55<br/> f6cb8343444771c3d03cc90e3ac5f76ff9a4cb9cd41e65c3b7f52b38b20c0c27</em></em></p><p><em><em>rule AnomaliLABS_Lazarus_wipe_file_routine {<br/> meta:<br/> author = "aaron shelmire"<br/> date = "2015 May 26"<br/> desc = “Yara sig to detect File Wiping routine of the Lazarus group”<br/> strings:<br/> $rand_name_routine = { 99 B9 1A 00 00 00 F7 F9 80 C2 61 88 16 8A 46 01 46 84 C0 }<br/> /* imports for overwrite function */<br/> $imp_getTick = "GetTickCount"<br/> $imp_srand = "srand"<br/> $imp_CreateFile = "CreateFileA"<br/> $imp_SetFilePointer = "SetFilePointer"<br/> $imp_WriteFile = "WriteFile"<br/> $imp_FlushFileBuffers = "FlushFileBuffers"<br/> $imp_GetFileSizeEx = "GetFileSizeEx"<br/> $imp_CloseHandle = "CloseHandle"<br/> /* imports for rename function */<br/> $imp_strrchr = "strrchr"<br/> $imp_rand = "rand"<br/> $Move_File = "MoveFileA"<br/> $Move_FileEx = "MoveFileEx"<br/> $imp_RemoveDir = "RemoveDirectoryA"<br/> $imp_DeleteFile = "DeleteFileA"<br/> $imp_GetLastError = "GetLastError"<br/> condition:<br/> $rand_name_routine and (11 of ($imp_*)) and ( 1 of ($Move_*))<br/> }</em></em></p>
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