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

Static analysis result for SHA-256 1acf8014622167df…

MALICIOUS

Office (OLE) / .XLSX

1.04 MB
MD5: 745944d616e2556787f9a1c722982fe2 SHA-1: 1762212ed7d3219c5f44882ed0579bcae75f336f SHA-256: 1acf8014622167df3e31517ab3a6a27969ee2aaf965a0ea60ec8e3c7bd3f68d1
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1059 Command and Scripting Interpreter T1203 Exploitation for Client Execution

The sample is an Excel file encrypted with the default VelvetSweatshop password to evade detection. It contains an embedded OLE object with the Equation Editor CLSID and a malformed Ole10Native stream, which is characteristic of exploits targeting CVE-2017-11882. No scripts were extracted from this sample, but the structural anomalies in the OLE object strongly indicate an exploit-based delivery mechanism.

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.