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

Static analysis result for SHA-256 0cad6525c647d211…

MALICIOUS

Office (OLE) / .XLSX

346.0 KB
MD5: addfeb527a9fd2a53741227b7c3c7f97 SHA-1: 8c8592a5ad65bdff1c9846129c3c2e8efe23d5bf SHA-256: 0cad6525c647d21165317dd7a16d30194e633beff5d77e747bdcd64a350165bb
160 Risk Score

Malware Insights

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

The sample is an encrypted XLSX file containing an Equation Editor OLE object, which is a known carrier for exploits. The presence of the 'CVE_2018_0798_EQUATION_NATIVE_ANOMALY' heuristic strongly suggests exploitation of this CVE. This technique is commonly used to execute arbitrary code, likely as part of a spearphishing attachment campaign.

Heuristics 5

  • 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.
  • 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-128)).
  • 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.