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

Static analysis result for SHA-256 9b88ac825c56b509…

MALICIOUS

Office (OLE) / .XLSX

1.21 MB
MD5: 168c2cabea51b16aa19a152a652254f5 SHA-1: 477715c6a9d3219ea85a60eac9c80af83a102357 SHA-256: 9b88ac825c56b50955cbc6211bb563f7334c51c2e90e3d2bfebefed817b4ad90
160 Risk Score

Malware Insights

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

The file is an encrypted OOXML spreadsheet identified by ClamAV as Xls.Downloader.af2fa5c5d0587870-9978799-0. Heuristics indicate it's an exploit carrier containing an Equation Editor OLE object, a common technique for delivering malware. The encryption with a default password further suggests malicious intent. No specific IOCs like URLs or hashes were extracted, but the structure strongly points to a downloader.

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.