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

Static analysis result for SHA-256 fcc7b40e69173818…

MALICIOUS

Office (OLE) / .XLSX

1.26 MB
MD5: 479ef6fdd48a05b4a68b4a4cc8059cb1 SHA-1: ce1568b2dc62c4e52c6d57443c1799a819ba3ef0 SHA-256: fcc7b40e69173818e71812e460cc9c87a60bc2e5aa3260118d78f722ac13a167
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1203 Exploitation for Client Execution

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object exhibits anomalies in its Ole10Native stream, suggesting it is designed to carry a payload. The presence of the Equation Editor OLE object is a strong indicator of exploitation, likely leveraging a known vulnerability such as CVE-2017-11882, to execute arbitrary code. The file is encrypted with a default password, a common tactic to hinder 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.
  • 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.