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

Static analysis result for SHA-256 517d3d23791c044f…

MALICIOUS

Office (OLE) / .XLSX

1.18 MB
MD5: 83ad6246c48bf6ff5e8aaae329a7eac1 SHA-1: 97670b973985707aca9ed2d400f9785e3042c511 SHA-256: 517d3d23791c044f84e03606bca1b18d17fba8542fc8594d0bb884d914b716fe
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1059 Command and Scripting Interpreter T1203 // a bit too generic, maybe T1203 if it is an exploit? No, T1203 is exploit for client application. Let's check. Yes, T1

The sample is a default-encrypted OOXML file containing embedded OLE objects with the Equation Editor CLSID, which is characteristic of CVE-2017-11882 exploits. The presence of a high-entropy Ole10Native stream with malformed sizing within the Equation object strongly indicates a payload delivery mechanism via this exploit. No scripts were extracted from this sample, but the exploit payload is binary data within thes OLE object.

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.