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

Static analysis result for SHA-256 afb357745f0ea33a…

MALICIOUS

Office (OLE) / .XLSX

812.5 KB
MD5: f582280284eb54e26a4daca9123842fb SHA-1: 07a66947094e202c5135ecb7b6e7fe7cafdbf3b8 SHA-256: afb357745f0ea33a54d8def1fcc1c0240f4c61daa42c059f1a4e3544215d2389
140 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, which is a known exploit carrier. Heuristics indicate a high likelihood of exploitation for CVE-2018-0798. The encrypted nature and the specific exploit vector suggest a downloader or dropper functionality, though no specific family can be identified without further analysis of the dropped payload.

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.
  • 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.
  • 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.