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

Static analysis result for SHA-256 90a74b59e44b4a76…

MALICIOUS

Office (OLE) / .XLSX

1.30 MB
MD5: cb678ea47f11c469ada898872208a391 SHA-1: c23fb0c7ed0d4d8719838a4a35e49712dad2b010 SHA-256: 90a74b59e44b4a76b3fceae61d803b866e58af51be0fafd422809d084093d6b2
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1559.001 Component Object Model Hijacking

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object is known to be used as a carrier for exploits, and the presence of a payload-like Ole10Native stream within it strongly suggests it's designed to deliver a secondary payload. The specific exploit mechanism points to the Equation Editor vulnerability.

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.