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

Static analysis result for SHA-256 3ed985723d058543…

MALICIOUS

Office (OLE) / .XLSX

1.29 MB
MD5: 1c0f585d5c5879b218ea8ee531bd0e45 SHA-1: 52c27b84093b16f543c69ebf0c4d65737d5350ac SHA-256: 3ed985723d0585433f5c23fa34ea383d5e65c0165f60c0f706178f6ccd5862f5
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1559.001 Component Object Model

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object exhibits anomalies, specifically an impossible Ole10Native header, suggesting it carries a malicious payload. The presence of multiple high-severity heuristics related to Equation Editor and OLE objects strongly indicates an exploit carrier designed to leverage these components for initial access.

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.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • 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.