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

Static analysis result for SHA-256 c13a3022f2212e4e…

MALICIOUS

Office (OLE) / .XLSX

269.5 KB
MD5: efdb3073607b0e44e67b7436fdb70f5b SHA-1: bac5f9c3aa6e6fae7034d6a1fc9197b1090b4f0e SHA-256: c13a3022f2212e4e16fb2147f6fd0c09ed4439a49b4313603a5e48b7b3174167
160 Risk Score

Malware Insights

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

The sample is a password-encrypted Excel file containing an embedded Equation Editor OLE object. Heuristics indicate this object is designed to exploit CVE-2018-0798, a vulnerability in Microsoft Equation Editor. This exploit likely serves as a carrier for a secondary payload, leading to arbitrary code execution.

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.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007+, AES-128)).
  • 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.