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

Static analysis result for SHA-256 7ef3cda5e36690ad…

MALICIOUS

Office (OLE) / .XLSX

344.0 KB First seen: 2022-04-12
MD5: 50ae810998dad5047e60b426afcb7db6 SHA-1: 27c9f3e79f8f2dc977af885a4f86ad71e2c16a03 SHA-256: 7ef3cda5e36690ad7131f38e5d74c3c99229d2ee93f723f7cd89e15a28b5b58b
160 Risk Score

Malware Insights

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

The file is a password-encrypted Office document that contains an Equation Editor OLE object. Heuristics indicate this object is anomalous and likely exploits CVE-2018-0798, a vulnerability in Equation Editor. This exploit is designed to execute arbitrary code, likely leading to the download and execution of a second-stage payload.

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.