Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 5b6283cd6a7027be…

MALICIOUS

Office (OLE) / .XLSX

129.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 0838266085a5cbd6a6f63a188804bf8b SHA-1: 964aba3de69f975a802394b64442b15b8614b2dd SHA-256: 5b6283cd6a7027beaa7bc89b3fbcb69e92186119feffd00a7f5a611e231bc62c
300 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File

The sample contains heavily obfuscated VBA macros, including a Workbook_Open auto-execution routine. These macros utilize `CreateObject` to instantiate `Wscript.Shell` and execute commands. The script attempts to download and run a VBScript from 'c:\programdata\yhjlswle.vbs' and a batch file from 'c:\programdata\ughldskbhn.bat', which in turn appears to execute a PowerShell command with a Base64 encoded payload. This indicates a downloader functionality aiming to fetch and execute a second-stage payload.

Heuristics 7

  • 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: Doc.Downloader.EmotetRed02220-9938909-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02220-9938909-0
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • 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 macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
7a075e02dc1e88807280b9b84946715e79a3c091d50391301434649c77b78ea1		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 12808 bytes

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