Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f79c328cb642e414…

MALICIOUS

Office (OLE)

28.0 KB First seen: 2012-06-14
MD5: 646ccd689978796b6d7932787686504b SHA-1: 7411ad6bf037c71e160944d6cb5046c5ac8b7d30 SHA-256: f79c328cb642e4141c75efb8330d67b925522174e6ffa7de6082cda2c7808d54
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The file is an OLE document containing a critical heuristic firing for a Laroux macro-virus marker, indicating the presence of malicious VBA code. The embedded document also shows suspicious static findings and a large slack anomaly, suggesting deliberate obfuscation or evasion. The presence of VBA macros points to an attempt to execute arbitrary code upon opening, likely as a payload delivery mechanism.

Heuristics 4

  • Excel 5 Laroux/Larou-CV macro-virus marker cluster critical OLE_XLS5_LAROUX_MACRO_VIRUS
    Legacy Excel workbook contains a Laroux/Larou-CV macro-virus marker cluster including auto_open execution and workbook/module replication strings. This is a narrow indicator for an infected legacy Excel macro workbook.
  • Embedded Office document has suspicious static findings critical EMBEDDED_OFFICE_CHILD_STATIC_TRIAGE
    A CFB/OLE Office document was found inside another file type and its carved contents matched Office exploit or payload heuristics. This catches wrapped exploit documents where the top-level file routes to a PE, archive, or generic scanner instead of Office.
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 18,587 bytes but its declared streams total only 0 bytes — 18,587 bytes (100%) live in unallocated sector slack. This is the canonical hiding place for pre-macro-era Office exploit payloads (XOR-encoded shellcode reached via a parser pointer-corruption bug in the document structure).
  • CFB header with no readable streams medium OLE_PARSE_EMPTY_STREAMS
    The file begins with a valid OLE2/CFB header but exposes no directory streams. A non-empty compound document with an unreadable directory is anomalous — it is seen with truncated/corrupt files and, more importantly, with content deliberately shifted off byte boundaries to defeat parsers while the host application still recovers the object.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_office_off00002765.ole embedded-office Embedded OLE/CFB Office body inside ole container at offset 0x2765 18587 bytes
SHA-256: 7047116445b449bc60917851a73f7c170fb2700ea3090c06cf8109bb56a2d4d1

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