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

Static analysis result for SHA-256 acc797b639923ca0…

MALICIOUS

Office (OLE) / .XLSX

1.19 MB
MD5: 5786287a21ec92fcf8f9f9f1aff53d42 SHA-1: e08ddafe3290c5dc5cee2877fe83f883b1b6d1b5 SHA-256: acc797b639923ca063809f50d4f19c2c6baf62e2887ee49127260107e7441b67
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an OOXML file that is encrypted with a default password and contains an Equation Editor OLE object. This object is known to be used as a carrier for exploits, specifically targeting vulnerabilities like CVE-2017-11882. The presence of an 'Ole10Native' stream anomaly within the Equation Editor object strongly suggests it's designed to deliver a secondary payload, likely an exploit.

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.