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

Static analysis result for SHA-256 307d44e277e186ca…

MALICIOUS

Office (OLE) / .XLS

496.1 KB Created: 1996-10-14 23:33:28 Authoring application: Microsoft Excel
MD5: 6a00ae0e9045dd60ce9863b92c2dcd57 SHA-1: 0f8f73381d3cefea6a1bc264f8711a4350ab58dd SHA-256: 307d44e277e186caea25df83eea1139a2143fd851b6995d7b801d50ca5d24271
100 Risk Score

Malware Insights

The sample is an Excel spreadsheet exhibiting a significant slack space anomaly and containing XOR-encoded strings with a key of 0xFC. While no VBA scripts were explicitly extracted, the presence of these indicators strongly suggests malicious intent, likely involving obfuscated code execution. The large slack space is a common technique to hide malicious payloads within Office documents.

Heuristics 2

  • XOR-encoded strings (key 0xFC) critical SC_XOR_ENCODED
    Found 7 Windows library/API name(s) XOR-encoded with single-byte key 0xFC: 'LoadLibraryA', 'GetProcAddress', 'VirtualAlloc', 'CreateProcessA', 'RegOpenKeyExA', 'RegOpenKeyExA', 'ShellExecuteA'
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 508,008 bytes but its declared streams total only 15,628 bytes — 492,380 bytes (97%) 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).