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

Static analysis result for SHA-256 fc53bd0d8c210935…

MALICIOUS

Office (OLE) / .XLSX

379.4 KB First seen: 2022-06-11
MD5: c92a61fe324fe5fd820abf52bcf8bd56 SHA-1: 7e3a7501965c8737b3663f0ffe22ffea1f9215e4 SHA-256: fc53bd0d8c2109355f4ef5c6d891072cc3c04ea60a3c82feb67b0174e1105282
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File T1559.001 Component Object Model Hijacking: Component Object Model

The sample is an encrypted Office document that contains an Equation Editor OLE object. Heuristics indicate this object is anomalous and likely exploits CVE-2018-0798. The document is also flagged as an exploit carrier, suggesting it is designed to deliver a malicious payload via this vulnerability.

Heuristics 6

  • 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.
  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • 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.