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

Static analysis result for SHA-256 8d40aa104142d63d…

MALICIOUS

Office (OLE) / .XLS

216.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: ee77fa2e79730b7e49d9e619be3e2ea0 SHA-1: 4c7f406b5d2125fc49cb79b9cbe6aac299e1f0fe SHA-256: 8d40aa104142d63d3f59696d6cce7787678b3b8537932b8da3620f89a146cd8f
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File

The XLS file contains an embedded PE executable and exhibits a large slack space anomaly, indicative of a packed or obfuscated payload. Heuristics also detected NOP sleds and XOR-encoded strings, common in malware. The presence of an embedded executable suggests this file is a dropper or loader for a secondary malicious component.

Heuristics 6

  • XOR-encoded strings (key 0xD5) critical SC_XOR_ENCODED
    Found 1 Windows library/API name(s) XOR-encoded with single-byte key 0xD5: 'kernel32.dll'
  • NOP sled detected high SC_NOP_SLED
    Found 20+ consecutive 0x90 bytes
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 221,215 bytes but its declared streams total only 24,565 bytes — 196,650 bytes (89%) 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).
  • Embedded PE executable high OLE_EMBEDDED_EXE
    MZ/PE header found inside document — possible embedded executable
  • NOP-equivalent sled detected medium SC_NOP_EQUIV_SLED
    Long run of 0x40 bytes
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://ocsp.verisign.com0
    • http://ocsp.thawte.com0
    • http://crl.thawte.com/ThawtePremiumServerCA.crl0
    • http://crl.verisign.com/tss-ca.crl0
    • http://crl.verisign.com/ThawteTimestampingCA.crl0
    • http://crl.thawte.com/ThawteCodeSigningCA.crl0
    • http://www.360.cn

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