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

Static analysis result for SHA-256 91377ef04cc38837…

MALICIOUS

Office (OLE) / .XLSX

1.21 MB
MD5: 5c29a5e79abdb210fbbec5e1a78cc0f4 SHA-1: 7632e461fb22e416b32baefb1686903574d0a0e9 SHA-256: 91377ef04cc388371a9cfc541a5495ec690fbb099075e402c51c83598d58db81
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted XLSX file that contains an embedded Equation Editor OLE object. This object is a known technique for delivering malicious payloads, often exploiting vulnerabilities within the Equation Editor itself. The high entropy of the OLE10Native stream suggests it likely contains executable content, though no specific payload could be extracted or reconstructed from the provided evidence.

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.