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

Static analysis result for SHA-256 46fc6bd623a690f8…

MALICIOUS

Office (OLE) / .XLSX

228.9 KB
MD5: 0193aca82acbba4004353cc61a526cfd SHA-1: 27b9f7396ac1ac67e5215b6e046e070eceb13313 SHA-256: 46fc6bd623a690f8b431b110bf5a0a1e030897c6d0f8945a9fb31e407a542d1f
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1068 Exploitation for Privilege Escalation T1203 Exploitation for Client Execution

The sample is a password-encrypted XLSX file using the default VelvetSweatshop password, a common technique to bypass security scanners. It contains an embedded OLE object (xl/embeddings/oleObject1.bin) that triggers CVE-2018-0798, as evidenced by the high-entropy native stream (olE10natIVE) and anomalous MTEF versioning. The combination of encryption and a specific Equation Editor exploit indicates a high probability of remote code execution (RCE) upon opening the document.

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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