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

Static analysis result for SHA-256 3dd0319d2db9152c…

MALICIOUS

Office (OLE) / .XLSX

2.44 MB
MD5: 057d4192ee12502f36e43afb4a31ded7 SHA-1: 3160faebfd65279fab3377e4408806884e2ee065 SHA-256: 3dd0319d2db9152ca37487aa94811dc974a6a8f98824c59b2a3deb760d7aa745
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an encrypted OOXML file containing an embedded Equation Editor OLE object. Heuristics indicate exploitation of CVE-2018-0798 via an anomalous Equation Editor native stream, which likely serves as a carrier for a malicious payload. The encrypted nature of the document prevents direct analysis of its content, but the presence of the exploit carrier strongly suggests a delivery mechanism for further malicious activity.

Heuristics 5

  • 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.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Default-encrypted OOXML contains embedded Equation Editor data with anomalous native stream bytes consistent with a CVE-2018-0798-style exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like.
  • 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.