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

Static analysis result for SHA-256 ccefd4773a2e34ac…

MALICIOUS

Office (OLE) / .XLSX

596.0 KB
MD5: c837486396bc7dff80f1c7ed98abd4b6 SHA-1: 9c8efdf43b884feea36424ded712a5d92d2fceab SHA-256: ccefd4773a2e34ac1f4f891b4fb947cd398476d663d52462e949c49961083822
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious File T1566 Phishing T1566.001 Spearphishing Attachment T1059 Command and Scripting Interpreter

The sample is a password-encrypted XLSX file that contains an embedded Equation Editor OLE object. Heuristics indicate this object is an exploit carrier for CVE-2018-0798, which is known to be used for delivering malicious payloads. The anomalous Equation Editor native stream suggests the exploitation of this vulnerability. No scripts or document body text were extracted, but the presence of the exploit carrier strongly indicates a malicious intent to compromise the user's system 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-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.