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

Static analysis result for SHA-256 5b389e6239f30d53…

MALICIOUS

Office (OLE) / .XLS

76.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 0bd229dbde5fa075603f881695949856 SHA-1: 85f88e6e0a6ed7a741b6ebd10e51228c79e4a524 SHA-256: 5b389e6239f30d537a5052dd535101d357425bbadb71d836af86897cec26c555
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 record overflow vulnerability. This vulnerability allows for arbitrary code execution, likely to download and run a secondary payload. The presence of VirtualAlloc, VirtualProtect, LoadLibrary, and GetProcAddress API calls further supports the execution of malicious code.

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=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 77,824 bytes but its declared streams total only 24,565 bytes — 53,259 bytes (68%) 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

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