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

Static analysis result for SHA-256 dd39fb5ed8791947…

MALICIOUS

Office (OLE) / .XLSX

1.26 MB
MD5: cf58a649833459488f2c6032539c9994 SHA-1: 36e757b650d49602687d5ae06c156a452408697a SHA-256: dd39fb5ed879194781e541f9616b25c6f7815fc1eff32e1ac429de6e1ae2bc27
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model

The sample is an OOXML file that is encrypted with a default password and contains an embedded Equation Editor OLE object. This object exhibits anomalies indicative of a payload, specifically an 'Ole10Native' stream within the Equation Editor object, which is a known carrier for exploits. The presence of the Equation Editor OLE object strongly suggests exploitation of a vulnerability within it for initial execution.

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.