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

Static analysis result for SHA-256 16b3f6cbd26ab10d…

MALICIOUS

Office (OLE) / .XLSX

136.0 KB First seen: 2022-08-25
MD5: 8f871aed93c64126652d24bb96f705df SHA-1: 764e2efc5c00ca0206e69fc7394ec7ef40d65fc5 SHA-256: 16b3f6cbd26ab10da7fcf6f631ee2cbe46e7dc295aaebb2c9ab24905bb7c5957
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The file is a password-encrypted Office document containing an Equation Editor OLE object. Heuristics indicate this object is an exploit carrier for CVE-2018-0798, a vulnerability in Equation Editor that allows for arbitrary code execution. The encrypted nature of the document prevents further analysis of its contents, but the exploit carrier is a strong indicator of malicious intent.

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.