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

Static analysis result for SHA-256 a27e5026c46cee38…

MALICIOUS

Office (OLE) / .UNO

40.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2026-05-10
MD5: 41bf95dea21cedae779343670c7ad4bb SHA-1: 855c83fc2bbdba31f952a226cff6596014370707 SHA-256: a27e5026c46cee38e34525ab3e6dfe7da3f26896cbf7246b68e5056e3f272522
100 Risk Score

Malware Insights

The file is an OLE document with a significant amount of slack space, indicating potential obfuscation or embedded malicious content. Although VBA macros could not be extracted due to an unsupported format, the document body presents itself as a series of official application forms for various permits. This suggests a social engineering attack aimed at tricking the user into interacting with the document in a way that could lead to further compromise.

Heuristics 2

  • Excel Index Array exploit — CVE-2008-3005 critical CVE likely CVE_2008_3005
    Legacy Excel workbook has the CVE-2008-3005 exploit shape: a compact BIFF8 FORMAT-index cluster paired with a normal XF table and a large unallocated OLE slack region used to stage the payload. The FORMAT pattern alone is not sufficient, so the rule requires the OLE slack payload-hiding context to keep false positives low.
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 40,927 bytes but its declared streams total only 21,308 bytes — 19,619 bytes (48%) 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).