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

Static analysis result for SHA-256 55e8338ed972e906…

MALICIOUS

Office (OLE) / .XLSX

575.5 KB
MD5: a5648afefb0367b7bb0cc999122cb3a5 SHA-1: afc203efcdb56a1288472f5d17f1d88811ba5b14 SHA-256: 55e8338ed972e9060ec15e298db60d4b81fbeeb8b53a50527be7cd5390fead3a
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious File T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The sample is an encrypted XLSX file containing an Equation Editor OLE object. Heuristics indicate exploitation of CVE-2018-0798 via an anomalous Equation Editor native stream, suggesting it's an exploit carrier. The default password encryption and the presence of an OLE object within the OOXML structure are common delivery methods for malicious payloads.

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.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • 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.