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

Static analysis result for SHA-256 fffe5fdbf0750c06…

MALICIOUS

Office (OLE) / .XLSX

1.24 MB
MD5: e2ab6d0f90bf3ea44084a2945e4f1eb9 SHA-1: d0a0802eb6a7253323a261bb0d20bcb2d7340353 SHA-256: fffe5fdbf0750c069521be1bd6836979049524e62474b2cd3a25f5ed69534a17
140 Risk Score

Malware Insights

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

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, specifically targeting vulnerabilities within the Equation Editor itself. The high-severity heuristics indicate that this object likely contains a malicious payload, suggesting an attack pattern involving a malicious attachment designed to exploit the Equation Editor vulnerability upon opening.

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.