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

Static analysis result for SHA-256 6d2ce50b7e9d93dc…

MALICIOUS

Office (OLE) / .XLSX

173.0 KB
MD5: d1bc8ff7c2ec8a769a2244a4bdaafac7 SHA-1: 46126252d1a345f08579f54a1d1975471969ec21 SHA-256: 6d2ce50b7e9d93dc7f714f24777bf2b671169960c9ab8c6e207433207cd99ac7
160 Risk Score

Malware Insights

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

The sample is a password-protected OOXML file that contains an embedded Equation Editor OLE object. Heuristics indicate this object is anomalous and specifically matches indicators for CVE-2018-0798, a vulnerability allowing for exploitation for client execution. The encrypted nature of the document suggests it is intended to bypass initial static analysis and deliver a malicious payload upon opening.

Heuristics 5

  • 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.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Default-encrypted OOXML contains embedded Equation Editor data with anomalous native stream bytes consistent with a CVE-2018-0798-style exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like.
  • 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.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007+, AES-128)).
  • 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.