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

Static analysis result for SHA-256 c1c9bbbc5182d7ad…

MALICIOUS

Office (OLE) / .XLSX

310.4 KB
MD5: 48e54e9aecf538385bc2a02a18613b9f SHA-1: f4b85cb0fbf0f3f60ab60d2540bf851a88f4c06a SHA-256: c1c9bbbc5182d7adc659bd46fd83c3d1339879b89b18fb429f12aa9fad294a44
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.002 Malicious File T1059 Command and Scripting Interpreter

The file is an encrypted Office document, identified as an exploit carrier due to its structure and the presence of an Equation Editor OLE object. The critical heuristic 'OLE_ENCRYPTED_AND_MALFORMED' indicates a malformed and encrypted package, likely designed to exploit a vulnerability such as CVE-2018-0798 within the Equation Editor component. This suggests the document is intended to download and execute a secondary payload upon opening.

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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