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

Static analysis result for SHA-256 f23f2b216032cb6b…

MALICIOUS

Office (OLE) / .XLSX

454.5 KB
MD5: 77a9d9aa87d47a9a4c5638d8b070354a SHA-1: fec5d873ebf94cd4eb23f4c79536d0de924b4728 SHA-256: f23f2b216032cb6bb6566f3d5315342f1132ed2a8badfb30cf71b7715b480258
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566.001 Spearphishing Attachment

The sample is an encrypted OOXML file identified as an exploit carrier. It contains an Equation Editor OLE object, which is a strong indicator of exploitation attempts targeting vulnerabilities such as CVE-2018-0798. The presence of an embedded OLE object within an encrypted document suggests a multi-stage attack designed to bypass initial detection. No specific family could be identified, but the exploit vector is clear.

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.