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

Static analysis result for SHA-256 d4c1b42be645dbb3…

MALICIOUS

Office (OLE) / .XLSX

632.4 KB
MD5: 5ed33a090ccefa4da82f1bc3d2597514 SHA-1: a28d3f45aa8314394ae1cd13ffa7727ac252be95 SHA-256: d4c1b42be645dbb3a48e3bc6a94d8b2a621bbe26efd2ba00c8347305f77b713c
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted Office document, identified as an exploit carrier due to embedded OLE objects, specifically the Equation Editor. The presence of CFB FAT corruption and default password encryption indicates a deliberate attempt to conceal malicious content. The exploitation of the Equation Editor OLE object is a known vector for delivering malware.

Heuristics 5

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Default-encrypted OOXML embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • 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.
  • Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE
    Default-password encrypted OOXML package contains embedded OLE object parts and additional activation/decoy parts. This layout is common in malicious Excel exploit delivery and requires inspecting the decrypted package.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
  • 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.