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

Static analysis result for SHA-256 623a7a3dd2a6c4c9…

MALICIOUS

Office (OLE) / .XLSX

634.5 KB
MD5: 2cf5be509c178fc150b0aa49a5f231bd SHA-1: 211c322e679d5085bdf13745010dcc0aa6ef4391 SHA-256: 623a7a3dd2a6c4c95fb9fc3aa622df05bebba54b36913ba0c2ff1e0a1096ac5d
120 Risk Score

Malware Insights

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

The sample is a password-encrypted Excel file that contains an embedded OLE object. Heuristics indicate this object is likely an Equation Editor exploit, a common method for delivering malicious payloads. The default password encryption suggests a common exploit carrier technique. The embedded OLE object is the primary indicator of malicious intent, likely leading to client execution.

Heuristics 4

  • 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.
  • 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.