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

Static analysis result for SHA-256 85d4e1e1bf4a1be0…

MALICIOUS

Office (OLE) / .XLSX

1.14 MB
MD5: 756561b005ea847ad7bca16643725466 SHA-1: 1055ac71513d193b1a5aebf7557b36f2d573923e SHA-256: 85d4e1e1bf4a1be06f3712d55c380ad1c91cab1cf52496e3a8b0b8911758ab05
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1068 Exploitation for Privilege Escalation T1203 Exploitation for Client Execution

The sample is an encrypted OOXML file that uses the default 'VelvetSweatshop' password to bypass static analysis. 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, CVE-2018-0802, or CVE-2018-0798. No scripts were extracted from this sample, but the structural anomalies in the OLE object strongly indicate a payload delivery mechanism via Equation Editor exploitation.

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.