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

Static analysis result for SHA-256 06f4eb2c9bdf7859…

MALICIOUS

Office (OLE) / .XLS

84.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 59619af1f6239b83bbb7221a38ea6ec4 SHA-1: 18274ce44156ae378088dc5a34f1d47ac6ec08b5 SHA-256: 06f4eb2c9bdf78597e186e347fd37c440a715041d266def198519075c84edd42
140 Risk Score

Malware Insights

The file is an Excel spreadsheet containing text that mimics legitimate application forms for various permits. Heuristics indicate the presence of XOR-encoded strings and PEB access, suggesting obfuscated malicious code within the document. The large slack space in the OLE structure is also anomalous. While no specific script was extracted, the combination of these factors points to a macro-enabled document designed to deceive the user.

Heuristics 3

  • XOR-encoded strings (key 0x97) critical SC_XOR_ENCODED
    Found 8 Windows library/API name(s) XOR-encoded with single-byte key 0x97: 'shell32.dll', 'shlwapi.dll', 'KERNEL32.DLL', 'LoadLibraryA', 'GetProcAddress', 'VirtualAlloc', 'VirtualProtect', 'RegOpenKeyExA'
  • PEB access via FS segment (x86) high SC_PEB_ACCESS
    PEB access via FS segment (x86)
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 86,016 bytes but its declared streams total only 21,308 bytes — 64,708 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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