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

Static analysis result for SHA-256 f3a8b1d242e1d620…

MALICIOUS

Office (OLE) / .XLSX

1.01 MB
MD5: 4d9474fca60fd54f2953d60899c45ee5 SHA-1: 0e8923ad08617902605c08a964d72559d0017b72 SHA-256: f3a8b1d242e1d620298d30c345eb4702379d512897f0ba76fea84b6991c61adb
140 Risk Score

Malware Insights

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

The sample is an OOXML file that is encrypted with a default password, indicating it's likely an exploit carrier. High-severity heuristics indicate the presence of a malicious Equation Editor OLE object, which is a known vector for delivering exploits. The specific OLE object structure suggests it carries a payload, likely for client-side 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.
  • 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.