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

Static analysis result for SHA-256 36b164253c39caee…

MALICIOUS

Office (OLE) / .XLSX

349.0 KB
MD5: b2ffdad319dac1c1386ace120fb12bd8 SHA-1: 987ee82e670006a2a065bcfe8b93fa2491824c23 SHA-256: 36b164253c39caee1822d74918430a3186916d74fe981ccb265547a4c320c47d
140 Risk Score

Malware Insights

The sample is an Office document that is both password-encrypted and malformed, indicating an attempt to hinder analysis. The critical OLE_ENCRYPTED_AND_MALFORMED heuristic firing suggests structural corruption within the encrypted package. While no document body or scripts were extractable due to encryption, the combination of encryption and malformation points to a malicious intent, likely to evade detection or obfuscate a secondary payload.

Heuristics 4

  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • Encrypted Office package with non-block-aligned cipher high OFFICE_ENCRYPTED_PACKAGE_MALFORMED
    EncryptedPackage cipher body is 322,040 bytes — not a multiple of the 16-byte AES block size.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007+, AES-128)).
  • Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML
    OLE EncryptedPackage decrypts with Excel's built-in VelvetSweatshop password. Office opens this transparently, and malware uses it to hide OOXML exploit parts from scanners that only inspect the outer OLE container.