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

Static analysis result for SHA-256 390b2e4c089f2896…

MALICIOUS

Office (OLE) / .XLSX

229.2 KB
MD5: e1f24e827fe14872df7fce40bbcbbd35 SHA-1: 97354e8b534abe7c659620d91bbfa493976de349 SHA-256: 390b2e4c089f28964617db439ed276304fe3e6a1a433b61a9ae3c1942676a57d
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566.001 Spearphishing Attachment

The sample is an encrypted Office document, identified as an exploit carrier due to the presence of an Equation Editor OLE object. High-confidence heuristics indicate exploitation of CVE-2018-0798 via anomalous Equation Editor native stream data. The document's encrypted nature and the specific exploit vector suggest it is designed to deliver a malicious 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.