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

Static analysis result for SHA-256 e59c621729584d74…

MALICIOUS

Office (OLE) / .XLSX

1.26 MB
MD5: ce65e9914b5a7cff0deb23216b142ff5 SHA-1: 3b2b9435e16244662743685bcda1bb9f9fcefd13 SHA-256: e59c621729584d742c21662f96703f4e51e6001fbf46d83dbea234d63da1c64b
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.002 Phishing: Spearphishing Attachment

The sample is an OOXML file encrypted with a default password, indicating it's likely an exploit carrier. High-severity heuristics confirm the presence of an Equation Editor OLE object, a known vector for delivering malicious payloads. The Equation Editor object contains an anomalous Ole10Native stream, suggesting it's designed to execute arbitrary code.

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.