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

Static analysis result for SHA-256 c5f3feba1650557f…

MALICIOUS

Office (OLE) / .XLSX

1.29 MB
MD5: a9072df610fdea0abc549f13b5aa1ac2 SHA-1: 1dd5b954f175983d4f8ca01de084a2c0c8bd2d40 SHA-256: c5f3feba1650557f3e44119133e1c7c35ce2c314d0c98ea3ca33030d75adf591
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Phishing: Spearphishing Attachment

The file is an OOXML document that is encrypted with a default password and contains embedded OLE objects, specifically identified as Equation Editor objects. High-severity heuristics indicate that these Equation Editor objects are likely exploit carriers, with one containing a payload-like Ole10Native stream. This strongly suggests the file is designed to exploit a vulnerability within the Equation Editor to achieve code 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.