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

Static analysis result for SHA-256 fc01b31e1464ab8b…

MALICIOUS

Office (OLE) / .XLSX

71.5 KB First seen: 2022-06-20
MD5: e60230e898db717ff314fb1d186488c0 SHA-1: 288079a3d0d91d26a9b0e4e1c8100c08e5dcb80f SHA-256: fc01b31e1464ab8b85c3f52187f71433c1635dd907cb05be9583cd6ddec1b149
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model

The sample is a password-encrypted XLSX file that contains an Equation Editor OLE object. Heuristics indicate this object is anomalous and specifically flags CVE-2018-0798, suggesting exploitation of this vulnerability for client execution. No document body or scripts were extractable due to encryption, but the presence of the Equation Editor exploit carrier is sufficient evidence.

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.