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

Static analysis result for SHA-256 0edfb83b551fd3ee…

MALICIOUS

Office (OLE) / .XLS

63.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: a918bc6addc1d1b222c1316b8d8b985a SHA-1: 2751d16bf3afd32405bd90d0718fcb04c69a8cf1 SHA-256: 0edfb83b551fd3eee6de15a9406052a2340b55794ea53ceb687d1f0213f14b51
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The critical CVE-2009-3129 heuristic indicates that this Excel file exploits a record overflow vulnerability to achieve code execution. High-severity heuristics for LoadLibrary and GetProcAddress suggest the loading and execution of malicious code, likely via a dropped payload. The large slack space in the OLE structure is also indicative of obfuscation or padding for exploit purposes.

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 64,512 bytes but its declared streams total only 24,565 bytes — 39,947 bytes (62%) 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