Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 17cf31ebf1291a80…

MALICIOUS

Office (OOXML) / .XLSX

92.0 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 12.0000
MD5: d7fefb17d55c555afaf15d8be0900ab5 SHA-1: 61d82cd56dcb787e137d0c41ee47be3204e43fdc SHA-256: 17cf31ebf1291a8036dee6611ece5051407349f7bd1fffc2d85d0377c79b9517
260 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample contains a Workbook_Open macro that is heavily obfuscated and uses CreateObject to execute a command. The macro attempts to download and run a second-stage payload from multiple URLs, including 'http://haarehouproudcuts.com/Merchan2/ARSf1LIcOauhgH1rDriH/'. The presence of Emotet-related heuristics and the ClamAV signature strongly indicate this is a downloader for the Emotet banking trojan.

Heuristics 6

  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • ClamAV: Xls.Downloader.EmotetRed02221-9938910-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.EmotetRed02221-9938910-0
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
de7bcbc45ff0a77d05d9af662bacc316e71be11a980e94f6673e556a5dd9d1bc
vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 12808 bytes
vbaProject_00.bin
4baf69552dbc1f9f2a59a6f84a1f5239d365767dd87c800d7efbe6bd93c27cc4
vba-project OOXML VBA project: xl/vbaProject.bin 37888 bytes