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

Static analysis result for SHA-256 bf9e02227cf9e3fa…

MALICIOUS

Office (OLE) / .XLSX

349.5 KB First seen: 2022-04-14
MD5: 97ca8783df53e174efa710e23130c1e9 SHA-1: 635f3160329a4345b82ac5445c945ca7ff2b2754 SHA-256: bf9e02227cf9e3fa591faedb27ecc64d547f89795b95ce5887b16d27c0ee914c
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a password-encrypted Office document that contains an Equation Editor OLE object. High-confidence heuristics indicate this object is an exploit carrier for CVE-2018-0798, likely designed to execute arbitrary code upon opening. No document body or script content was extractable due to encryption, but the presence of the Equation Editor exploit is sufficient to infer the attack pattern.

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)).
  • 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.