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

Static analysis result for SHA-256 e4d9dff7c8132e10…

MALICIOUS

Office (OLE) / .XLSX

344.0 KB First seen: 2022-04-13
MD5: 1c81663166558d6fefd63b49f4b6cdcf SHA-1: bdbd041b1347263a5bef6dddae74412beafbc313 SHA-256: e4d9dff7c8132e1091e8a4c1a668729c9b5ef48c0a265c591005bf092c1bde24
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a password-encrypted XLSX file that contains an Equation Editor OLE object. High-confidence heuristics indicate this object is an exploit carrier for CVE-2018-0798, a vulnerability in Equation Editor. The encrypted nature of the document prevents further static analysis of its contents, but the presence of the exploit carrier strongly suggests it's designed for initial execution.

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.