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

Static analysis result for SHA-256 f431d4f1d2cedc73…

MALICIOUS

Office (OLE) / .DOC

123.5 KB
MD5: 33a862d86e95e66d9a8912c43d31b70c SHA-1: a095dd8a0a49d4496fcc5ddc22a037c4c9f238e7 SHA-256: f431d4f1d2cedc732b970512247d09a44c0966b0f3d8e7ffaf1e6aa8060d6a78
220 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1105 Ingress Tool Transfer T1027 Obfuscated Files or Information

The sample exhibits high-confidence heuristics indicating the use of WinExec, LoadLibrary, and GetProcAddress APIs, along with XOR-encoded strings. The OLE slack anomaly suggests potential obfuscation or embedded malicious content. These indicators point towards a downloader or droppper functionality, aiming to fetch and execute further stages. No specific family could be identified.

Heuristics 5

  • XOR-encoded strings (key 0x04) critical SC_XOR_ENCODED
    Found 8 Windows library/API name(s) XOR-encoded with single-byte key 0x04: 'kernel32.dll', 'wininet.dll', 'VirtualAlloc', 'VirtualAllocEx', 'CreateProcessA', 'InternetOpenA', 'InternetOpenUrlA', 'WriteProcessMemory'
  • Reference to WinExec API high SC_STR_WINEXEC
    Reference to WinExec API
  • 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 126,464 bytes but its declared streams total only 31,351 bytes — 95,113 bytes (75%) 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).

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