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

Static analysis result for SHA-256 f11ea6a7155be752…

MALICIOUS

Office (OLE) / .XLSX

2.10 MB
MD5: ad384e8c8855bc77a4e28d48fe1ceda1 SHA-1: 2f5811ece35653b1385604d1c98c7571e664674d SHA-256: f11ea6a7155be75272d56249aaacd080aa834c25bc672cff5f88e1fcf7617b2c
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object is a known exploit carrier, and the anomaly in the Ole10Native stream suggests it is designed to deliver a payload. No document body or scripts were extractable, but the presence of the Equation Editor OLE object strongly indicates an exploit delivery attempt.

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.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • 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.