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

Static analysis result for SHA-256 d6bde59751062de8…

MALICIOUS

Office (OLE) / .XLSX

288.7 KB
MD5: 94803e577febd5fedc5eb5df83cb103d SHA-1: c81568b01f019eafd402d7eb9f2d017d3f7c6aa0 SHA-256: d6bde59751062de81addae2e9d44c77955f175310a79a5e0c80da80a742d3b7c
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample is a password-encrypted Excel file that contains an embedded Equation Editor OLE object. This object exhibits anomalies consistent with CVE-2018-0798, indicating it's designed to exploit this vulnerability for initial execution. The file's structure and the presence of the Equation Editor exploit suggest it's a carrier for a malicious payload, likely delivered via social engineering as a spearphishing attachment.

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.