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

Static analysis result for SHA-256 b873bae68a9f7ed6…

MALICIOUS

Office (OLE) / .XLSX

1.16 MB
MD5: 65ff82cc0724d5768fb84e93268ef892 SHA-1: 59873a5cce4e84a78c04cfb8d5d0d7d714619487 SHA-256: b873bae68a9f7ed6ab8b216350ee92473b971793caffe8c591cc76ec09fe8d7b
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 is known to be used as an exploit carrier. The presence of the 'OLE_EQUATION_EDITOR' and 'OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY' heuristics strongly suggests that this object is being used to deliver a malicious payload, likely exploiting a known vulnerability within the Equation Editor. The file is encrypted with a default password, indicating an attempt 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.