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

Static analysis result for SHA-256 8778d7d09bfdd15b…

MALICIOUS

Office (OLE) / .XLS

156.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 9d2d4e97dd399f340f1bc0fdc03bbc48 SHA-1: bd392986272564f92a8f329fb40a7cf7129530b6 SHA-256: 8778d7d09bfdd15b79711db4bfde107180ab5f2e3335996f81e772843ad16e7d
240 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 exploits a heap overflow vulnerability to achieve code execution. The presence of VirtualProtect, LoadLibrary, and GetProcAddress API calls strongly suggests that the exploit is used to load and execute a malicious payload. The large slack space and appended payload bytes further support this, indicating a packed or obfuscated secondary stage.

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 159,744 bytes but its declared streams total only 24,565 bytes — 135,179 bytes (85%) 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).
  • OLE file has appended executable-looking payload bytes high OLE_APPENDED_PAYLOAD
    OLE compound file contains a large high-entropy region beyond the declared major streams and that region includes shellcode, PE, or loader API markers. This is a payload-carrier signal, not a specific CVE attribution by itself.
  • Reference to VirtualProtect API medium SC_STR_VIRTUALPROTECT
    Reference to VirtualProtect API

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