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

Static analysis result for SHA-256 ff083c7aae0fdc86…

MALICIOUS

Office (OLE) / .XLSX

229.3 KB
MD5: 708a8938afe1bd63eef3c27d946acc5f SHA-1: 176177a2cc37ad696a1fb7fceb735dba35b51b46 SHA-256: ff083c7aae0fdc8630cc507a3dce9787d76fadd9446f074ef9a01c168b6595af
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.001 Malicious Link: Malicious File T1566.001 Phishing: Spearphishing Attachment T1059 Command and Scripting Interpreter

The sample is an encrypted Office XLSX file that contains an embedded Equation Editor OLE object. Heuristics indicate this object is malformed and likely exploits CVE-2018-0798. The encryption and malformed object suggest it's designed to deliver a malicious payload upon opening, likely through a phishing or social engineering lure.

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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