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

Static analysis result for SHA-256 5b58e3dc01d21743…

MALICIOUS

Office (OLE) / .XLSX

179.5 KB First seen: 2022-04-27
MD5: 19f1ccfe07ff4c65663591845abf585f SHA-1: 79cd5463805bf07473d6bc2bd17740a0d238e6d5 SHA-256: 5b58e3dc01d217439703a3ff88b6235485ab62ae52c65d831aa692aec9b6340e
160 Risk Score

Malware Insights

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

The sample is an encrypted Office document containing an Equation Editor OLE object. Heuristics indicate this object is anomalous and likely exploits CVE-2018-0798, a known vulnerability allowing for arbitrary code execution. The document's encrypted nature and the presence of an exploit carrier suggest it is intended to deliver a malicious payload upon opening.

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)).
  • 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.