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

Static analysis result for SHA-256 055b91c51b01f7bf…

MALICIOUS

Office (OLE) / .VIR

71.0 KB Created: 1601-01-01 00:00:00 Authoring application: Microsoft Word 6.0
MD5: fba268d593fc3f1c123d59636d2fcfa9 SHA-1: 9a72dce1928522e95e8a5b6f4cdcb48c0b37f772 SHA-256: 055b91c51b01f7bf69451f5730d2319a9cf1c7450fe8309da3bfcdae45d601ee
120 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is an OLE file with significant slack space and anomalous stream parsing, indicating potential obfuscation or deliberate corruption to evade detection. The document body contains what appear to be internal filenames and macro names, suggesting it was designed to execute embedded code. The embedded OLE object is the primary indicator of malicious intent.

Heuristics 3

  • 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 60,927 bytes but its declared streams total only 0 bytes — 60,927 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_off00002e01.ole
48d8476b9459fbc9b0e3ecd972a8d15fc3d59211c7efc6c8098cdaf39a016dba
embedded-office Embedded OLE/CFB Office body inside ole container at offset 0x2E01 60927 bytes