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

Static analysis result for SHA-256 f048d315ade0319c…

MALICIOUS

Office (OLE) / .XLSX

343.5 KB First seen: 2022-04-10
MD5: 0b7ca6ea5e6116cf9ca6944a1ada8a03 SHA-1: 6cf57789fd3e264de3ca48b3306f3411f0d67e3b SHA-256: f048d315ade0319c13872d4f31b528f995aa177d33ca9e42e1dbc6f03ca41c20
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. Heuristics indicate this object is an exploit carrier for CVE-2018-0798, a vulnerability in Microsoft Equation Editor. This vulnerability allows for arbitrary code execution when the document is opened. No scripts were extracted, but the presence of the exploit carrier strongly suggests the document's purpose is to deliver 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.