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

Static analysis result for SHA-256 846749404c08e04f…

MALICIOUS

Office (OLE) / .XLSX

473.5 KB
MD5: 854d0a9ca8abc211b1c3fff0957f7639 SHA-1: 14d34930877a3775a7dbfb64c4e34ae7e8d4e01d SHA-256: 846749404c08e04fe08affd717f1d9deddd93288a7e37f7813ab3f3a799e97c6
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an encrypted OOXML file that contains an embedded Equation Editor OLE object. Heuristics indicate exploitation of CVE-2018-0798, a vulnerability in Equation Editor, which is a common method for initial execution. The document is encrypted, preventing further analysis of its content or embedded scripts, but the presence of the exploit carrier strongly suggests a malicious intent to execute code.

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.