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

Static analysis result for SHA-256 3af808386346b499…

MALICIOUS

Office (OLE) / .XLSX

1.30 MB
MD5: 60b356940d743657fadce81baf654ef8 SHA-1: 27f0a83d9953c52c97c1b71c8adf2379922c8b80 SHA-256: 3af808386346b49940aa6160096c4ad22a9d11bd8f9aeee3aeee4218e1489ecd
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.002 Phishing: Spearphishing Attachment

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object is known to be used to deliver exploits, and the anomaly detected in the Ole10Native stream suggests it carries a payload. The specific exploit and payload are not detailed in the static analysis, leading to an 'unknown family' classification.

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.