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

Static analysis result for SHA-256 ae27ebe2e77f0b90…

MALICIOUS

Office (OLE) / .XLS

88.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 3c1514f1476431026f5744863c508958 SHA-1: 07dd7b38d59e33485bf9653bf2f053575d65e50b SHA-256: ae27ebe2e77f0b9023d454b6893c72f22ec45795b3c76262823e7dd36c6ef5f9
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File

The critical heuristic firing for CVE-2009-3129 indicates that this Excel file is designed to exploit a buffer overflow vulnerability. High severity heuristics for LoadLibrary and GetProcAddress, along with a medium severity heuristic for VirtualProtect, suggest that the exploit likely leads to the execution of injected code. The OLE slack anomaly further supports the presence of malicious content within the file structure. No specific family could be identified, but the exploit mechanism is clear.

Heuristics 5

  • 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 90,624 bytes but its declared streams total only 24,565 bytes — 66,059 bytes (73%) 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 VirtualProtect API medium SC_STR_VIRTUALPROTECT
    Reference to VirtualProtect API