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

Static analysis result for SHA-256 a2bff468c13047c6…

MALICIOUS

Office (OLE) / .XLSX

344.0 KB First seen: 2022-04-11
MD5: 1e7ad34697a7ba2d73e805080c226db7 SHA-1: 6a6ff84ea199263ba74f3f5f374da5d815cc68a5 SHA-256: a2bff468c13047c6a42de63b98f831b93d8c17f30c917d9241ed9492538d3ca4
120 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model

The sample is a password-encrypted Office document, a common technique for obfuscating malicious content. Heuristics indicate it contains an Equation Editor OLE object, which has historically been used to deliver exploits. The encryption prevents direct analysis of the document body, but the presence of the OLE object strongly suggests an exploit delivery mechanism.

Heuristics 4

  • 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.
  • 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.