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

Static analysis result for SHA-256 81a8b1c4a242da76…

MALICIOUS

Office (OLE) / .XLSX

1.41 MB
MD5: ed17d97f91ffda0f0fd9ce542155aae8 SHA-1: 0cd007398e57145c35bfb438c625b8ddac4b20ab SHA-256: 81a8b1c4a242da766e6496ee0d3a4f43f5bb2cdbec9ffa4bc68d1296c20cc267
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter T1083 System Driver Commands T1566 Phishing T1071 Application Layer Compromise

The file's structure, including the default-encrypted OOXML package, the presence of the Equation Editor OLE object (with a malformed Ole10Native stream), and the decrypted content, strongly indicates an attempt to exploit CVE-2017-11882 or similar Equation Editor vulnerabilities. The file attempts to execute arbitrary code by leveraging a legacy component with known weaknesses. The URL extraction further supports the delivery of a malicious payload. The high heuristic scores confirm the suspicious nature of the file.

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.