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

Static analysis result for SHA-256 bf5c8ef0265f1282…

MALICIOUS

Office (OLE) / .XLSX

980.5 KB
MD5: 8bd1428edcbc6d915fcb023507f63e32 SHA-1: b293cfebe2ac56a5df9d208e9aa44810c7db4bff SHA-256: bf5c8ef0265f1282d4f732823a4197b06d3d2c3f53242e47223d1077595089c4
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1566 Phishing T1204.002 Malicious File: User Execution of Malicious Code

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 within the Equation Editor itself. The presence of an Ole10Native stream anomaly within the Equation Editor object strongly suggests it is designed to execute a payload.

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.