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

Static analysis result for SHA-256 b7ee3ada772d88b8…

MALICIOUS

Office (OLE) / .XLSX

1.19 MB
MD5: f61308f87b0af6dfc5433561025f9ab1 SHA-1: ad4bd9e24ea51bc8d58dd38f628b69fb87476a5c SHA-256: b7ee3ada772d88b86d6f285aecbf7b0ab5273522af3766223b06c3163d48991c
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 'VelvetSweatshop' default password to bypass static analysis. It contains an embedded OLE object with the Equation Editor CLSID and a malformed Ole10Native stream, which is a classic signature of the Equation Editor exploit (CVE-2017-11882/CVE-2018-0802). No scripts were extracted from this sample, but the structural anomalies in the OLE object are highly indicative of a payload delivery mechanism via memory corruption.

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.