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

Static analysis result for SHA-256 0f25ea72a28dd3ec…

MALICIOUS

Office (OLE) / .XLSX

2.10 MB
MD5: f3564d988793a25af990dfcf5eac9a56 SHA-1: aee26a7baac909134597c13418f15ba31c8caa50 SHA-256: 0f25ea72a28dd3ec4fb241de86ec2a01d77cf6341a51b66bce5fd2fdc58d4319
120 Risk Score

Malware Insights

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

The file is a password-encrypted Excel spreadsheet that contains an embedded OLE object. Heuristics indicate this OLE object is likely an exploit carrier for Equation Editor, a common vector for delivering malicious payloads. The default password encryption suggests a common, albeit unsophisticated, method of hiding the exploit. The presence of an embedded macro-enabled document further supports the exploit carrier hypothesis.

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.