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

Static analysis result for SHA-256 d4eee88b95366d3b…

MALICIOUS

Office (OLE) / .XLSX

321.1 KB
MD5: b24cc76098fd1ecd0b8d4ec34123084e SHA-1: 3de9c3d03e5e1e4a4522d38b56313553734001bd SHA-256: d4eee88b95366d3b6f77ba4da420024e82d970e182572a685e1524c538839cf2
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a password-encrypted XLSX file that contains an embedded OLE object, specifically an Equation Editor object. High-severity heuristics indicate this object is anomalous and exploits CVE-2018-0798. This suggests the file is designed to leverage the Equation Editor vulnerability for initial execution, likely leading to the download and execution of a second-stage payload. The encryption and malformed nature of the OLE object further support its role as an exploit carrier.

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.

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