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

Static analysis result for SHA-256 5579366a43ab54b4…

MALICIOUS

Office (OLE) / .XLSX

317.5 KB
MD5: d3c81cb4c062ae5ef1431bb02fbc08a2 SHA-1: c65279361dd9837d3974164ac8471f3876c4574a SHA-256: 5579366a43ab54b489d5dea06fbe0dc022f9745418b470b59f00c57df46a08ac
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.002 Malicious File T1059 Command and Scripting Interpreter

The sample is an encrypted Office XLSX file. Heuristics indicate it is an exploit carrier utilizing an Equation Editor OLE object, specifically triggering the CVE-2018-0798 vulnerability. This suggests the document is designed to exploit a known vulnerability in the Equation Editor component to execute malicious code 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.