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

Static analysis result for SHA-256 35e085a4c493e204…

MALICIOUS

Office (OLE) / .XLSX

928.3 KB
MD5: ceed8d513e143b89d08c7338b210e0e9 SHA-1: 3f3766258a0b077eff5217b5aab2091566458d60 SHA-256: 35e085a4c493e20455a4ab8387f79d2ceaba67d4428e8952c0ff84e5e2f16a71
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1059 Command and Scripting Interpreter

The file is an encrypted Office document that utilizes default encryption, a common tactic for obfuscation. High-severity heuristics indicate the presence of an Equation Editor OLE object which contains an anomalous Ole10Native stream, strongly suggesting it's an exploit carrier. This points towards an attack pattern leveraging vulnerabilities in the Equation Editor to deliver a 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.