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

Static analysis result for SHA-256 1a1ba4ec52cedb1b…

MALICIOUS

Office (OLE) / .XLSX

1.31 MB
MD5: 785885abe4d9d4685f682beab7c2bdb1 SHA-1: 62bbcaa2c63f4efd619eade587c4b4bd45e5e060 SHA-256: 1a1ba4ec52cedb1b3ca9323b36ae0541e60a0ae366784e1825fb055667f25fab
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object carries a payload-like Ole10Native stream, indicating it's likely used to exploit a vulnerability in the Equation Editor component. The file's structure and the presence of the Equation Editor exploit carrier strongly suggest it's designed to deliver a secondary malicious payload.

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.