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

Static analysis result for SHA-256 5d247d1569562c31…

MALICIOUS

Office (OLE) / .XLS

224.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 18df9c11d6df727e42d16adfc4d15f89 SHA-1: 51ba90eb46991e2d96f94d57c353577f46298164 SHA-256: 5d247d1569562c31712003a6eae230fbb3eb9ddd4b2cb825a4e8b6676cf6d657
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a malicious Microsoft Excel file that exploits CVE-2009-3129, a record overflow vulnerability. This vulnerability allows for the execution of arbitrary code on the victim's machine. The presence of LoadLibrary and GetProcAddress API calls further suggests the loading and execution of malicious code. No specific family could be identified.

Heuristics 4

  • CVE-2009-3129 — Excel FEATHEADER record overflow critical CVE exact CVE_2009_3129
    Workbook BIFF stream contains a FEATHEADER (Feature Header) record with anomalous size (record_size=23, isf=2, cbHdrData=4294967295). Legitimate FEATHEADER records are tiny (<100 bytes) and carry cbHdrData values that fit in the record body; the value here is the documented CVE-2009-3129 exploit primitive — cbHdrData drives a memcpy with attacker-controlled size, leading to memory corruption and code execution in Excel 2007/2003.
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 229,399 bytes but its declared streams total only 24,565 bytes — 204,834 bytes (89%) 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).

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