Conti — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 026868713d60e679…

MALICIOUS

Office (OLE) / .XLS

247.0 KB Created: 2021-09-29 19:38:56 Authoring application: Microsoft Excel First seen: 2022-03-15
MD5: b0ab12a5a4c232c902cdeba421872c37 SHA-1: a8e7659942cc19f422678181ee23297efa55fa09 SHA-256: 026868713d60e6790f41dc7046deb4e6795825faa903113d2f22b644f0d21141
308 Risk Score

Malware Insights

Conti · confidence 95%

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

The sample is an Excel file containing obfuscated VBA macros, specifically a Workbook_Open auto-execution routine. This routine uses CreateObject and CallByName to execute shell commands, likely to download and run a second-stage payload. The ClamAV detection name 'Xls.Dropper.Conti-9937576-0' strongly suggests the Conti ransomware family.

Heuristics 8

  • 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.Dropper.Conti-9937576-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Conti-9937576-0
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName 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
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
2ac473742638c92e7948f600984bce765116535890ee793176a732e39319c332		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 6931 bytes

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