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

Static analysis result for SHA-256 1f0f51e7fa002eaa…

MALICIOUS

Office (OLE) / .XLSX

2.42 MB
MD5: daaf7ec8ecff429fb6a07bf4d56ead24 SHA-1: ae1ddaf703fd3444b909016b1322082203d34713 SHA-256: 1f0f51e7fa002eaaf850e6a8a73beaa687d583a86af2954ae8cb9bd4ca6d22a5
180 Risk Score

Malware Insights

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

The file is an encrypted OOXML document that contains an embedded Equation Editor OLE object. Heuristics indicate that this object is anomalous and likely exploits CVE-2018-0798, a vulnerability in Equation Editor, to deliver a payload. The default password encryption further suggests malicious intent. No document body or scripts were extractable, but the presence of the exploit carrier points to a delivery mechanism for a second-stage malicious payload.

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.

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