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

Static analysis result for SHA-256 5c543db8d1df71ab…

MALICIOUS

Office (OLE) / .XLSX

118.5 KB First seen: 2022-04-28
MD5: 9938db4f22a61319c0bc58016db23be5 SHA-1: 87c5abbdee9d2a3451abe7e23e1faf722fdb7f52 SHA-256: 5c543db8d1df71ab122febebba37319f8aca43d6f364cc94a9bfc8a5fef589fe
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file is a password-encrypted Office document containing OLE objects, specifically an Equation Editor object. High-severity heuristics indicate this object is an exploit carrier for CVE-2018-0798, designed to execute arbitrary code upon opening. The document's encrypted nature and the presence of an exploit carrier strongly suggest it was delivered as a malicious attachment.

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.