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

Static analysis result for SHA-256 aa19e20da236101d…

MALICIOUS

Office (OLE) / .XLSX

95.3 KB
MD5: c2e5b1d0b5b67f0feddb3f3ce0f70f31 SHA-1: e4a64fd0e74d418511dbbf5a38ad5362674b1f53 SHA-256: aa19e20da236101d49578f4d35d9a3429da6b8393dcc46bf931eb68cc46700da
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing

The sample is an encrypted Office XLSX file. Heuristics indicate it contains an embedded Equation Editor OLE object, which is a known exploit carrier for vulnerabilities such as CVE-2018-0798. The document is encrypted with a default password and exhibits malformed structures, suggesting it's designed to exploit these weaknesses for initial execution. No scripts were extracted, and the document body is inaccessible due to encryption.

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.