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

Static analysis result for SHA-256 35f0062df5960256…

MALICIOUS

Office (OLE) / .XLSX

63.4 KB First seen: 2023-07-16
MD5: 33d31d0964520dbe0a990d52b638efea SHA-1: 2204d2c2b0fd0227827e2cde43865b543d221234 SHA-256: 35f0062df59602561a200293799a9e023b24ee1d1b69eda6ca28b435ddc9d3e6
240 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The sample is a password-encrypted Office document, identified as a malicious dropper by ClamAV. It contains an Equation Editor OLE object, a known exploit carrier, and exhibits characteristics of an exploit document. The encryption and malformed structure suggest an attempt to obfuscate malicious content.

Heuristics 6

  • 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.
  • ClamAV: Doc.Dropper.Agent-6872524-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6872524-0
  • 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.