Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b53c7297635119a4…

MALICIOUS

Office (OLE)

104.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: c9a2df4579695fa1982cd9ec325c5894 SHA-1: a8b9a4aaa97688dc4d6d132debd6c337fb07a20f SHA-256: b53c7297635119a4e40bd3a1d9ca18729641ebfca5c437f9e7279700e38c0762
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The critical heuristic firing for CVE-2009-3129 indicates that this Excel file is designed to exploit a buffer overflow vulnerability. The presence of VirtualAlloc, VirtualProtect, LoadLibrary, and GetProcAddress API calls further suggests that the exploit likely involves memory allocation and loading of malicious code. The large slack space in the OLE structure is also a common characteristic of exploit documents.

Heuristics 6

  • 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=22, isf=4, cbHdrData=4). 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 107,008 bytes but its declared streams total only 24,565 bytes — 82,443 bytes (77%) 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).
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • Reference to VirtualProtect API medium SC_STR_VIRTUALPROTECT
    Reference to VirtualProtect API