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

Static analysis result for SHA-256 f26fa93f4a4f7cdd…

MALICIOUS

Office (OLE) / .XLSX

2.63 MB
MD5: dcc9a8a0a5aebaf8ac840e5f8b764972 SHA-1: 3fee8c74b472d8d36f5b6606402bc20ca6bfa578 SHA-256: f26fa93f4a4f7cddc3dc8d58d9330dc173b8249d022f104aac545fe168fccb70
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object is flagged as carrying a payload anomaly, suggesting it's used to deliver a secondary exploit or malware. The encryption with a default password and the presence of exploit carrier shapes further indicate malicious intent. No specific family is identified due to the lack of script content or further indicators.

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.