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

Static analysis result for SHA-256 4411b4a05f3bc654…

MALICIOUS

Office (OLE) / .XLSX

1.49 MB
MD5: 31b142cebbf97b880ead6a2dc3f415e2 SHA-1: b8b33c7492e0c6a25b2677f1126663d06a91fc2c SHA-256: 4411b4a05f3bc654dc86eba66de02e9a20751357b57a411468eee55cf3c879ec
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link

The sample is an encrypted OOXML file that contains an embedded Equation Editor OLE object. This object carries a payload-sized Ole10Native stream, indicating it's likely an exploit carrier. The presence of the Equation Editor OLE object strongly suggests exploitation of a vulnerability within it, commonly used for initial access.

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.