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

Static analysis result for SHA-256 d39993171762ba62…

MALICIOUS

Office (OLE) / .XLSX

313.5 KB
MD5: 80c38e7a042e5418e61c8c21cb4f3f3c SHA-1: e12e5ad0cd673fa13b41d16a172564b74a949bb6 SHA-256: d39993171762ba62999d06ba6425836e36189d7a991c2a8da07bb2b3a0ad75f8
120 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted Excel spreadsheet. Heuristics indicate it contains an embedded OLE object, specifically identified as an Equation Editor exploit carrier. This strongly suggests the file is designed to leverage vulnerabilities within Equation Editor to execute malicious code upon opening. The encryption is a common tactic to evade initial static analysis.

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.