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

Static analysis result for SHA-256 d571f14d96b2e3a1…

MALICIOUS

Office (OLE) / .XLSX

1.11 MB
MD5: 224e82a33d914f2dbcbcaac8361a9682 SHA-1: da11e1f609ae7e1c2ff25530820514687d10236d SHA-256: d571f14d96b2e3a1edcf7743486975b96a675e7f73933c7bf32861bda22e7871
160 Risk Score

Malware Insights

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

The file is an encrypted Office document containing an embedded Equation Editor OLE object, a known exploit carrier. ClamAV identified it as a downloader. The encryption and embedded exploit object strongly suggest it's designed to execute a malicious payload upon opening.

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.
  • ClamAV: Xls.Downloader.af2fa5c5d0587870-9978799-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.af2fa5c5d0587870-9978799-0
  • 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 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.