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

Static analysis result for SHA-256 71c5e30cb3250f58…

MALICIOUS

Office (OLE) / .XLSX

237.0 KB First seen: 2022-07-12
MD5: 54a5599f720df8dccdca52f82144464c SHA-1: 410757acce69f743077cfdf68bafa8ca0be86c43 SHA-256: 71c5e30cb3250f58b539b70a94f80fe7d16c964b1af43c3a604834cc07b8dd7a
160 Risk Score

Malware Insights

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

The file is an encrypted Office document containing an Equation Editor OLE object. Heuristics indicate it is likely an exploit carrier for CVE-2018-0798, which allows for arbitrary code execution when the Equation Editor is loaded. The document's encrypted nature and the presence of exploit-related objects strongly suggest it is intended to deliver a malicious payload.

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.