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

Static analysis result for SHA-256 f4159825f4db2e14…

MALICIOUS

Office (OLE) / .XLSX

224.0 KB First seen: 2022-05-20
MD5: 4aed8d2a71c1585584991748a730ffdd SHA-1: 46b0bb540ea6ae963286cf70d2da73ceb84bf1d7 SHA-256: f4159825f4db2e144ae356e67c360949c6abd85b910726425ddf68cbae1d72b3
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious File T1059 Command and Scripting Interpreter

The file is an encrypted Office document that contains an embedded Equation Editor OLE object. This object exhibits anomalies consistent with the Equation Editor vulnerability (CVE-2018-0798), indicating it's likely used as an exploit carrier. The document's encrypted nature and the presence of exploit-related OLE objects suggest it's designed to deliver a malicious payload upon opening, likely by exploiting the Equation Editor vulnerability.

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.