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

Static analysis result for SHA-256 acfd5b8146df0edf…

MALICIOUS

Office (OLE) / .XLSX

343.0 KB First seen: 2022-04-11
MD5: b81925729c5d1913d7a54b319c3f17c7 SHA-1: 2bd43e715d92d8275288b95318606baa0bf7fb89 SHA-256: acfd5b8146df0edf4efb2e7cf78d22499902893d30d75797cf8083442ca5aa56
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a password-encrypted XLSX file that contains an Equation Editor OLE object. This object exhibits anomalies consistent with CVE-2018-0798, indicating it's likely an exploit carrier. The encryption and the presence of OLE objects suggest the document is designed to exploit a vulnerability in the Equation Editor to achieve arbitrary code execution upon opening.

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)).
  • 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.