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

Static analysis result for SHA-256 d3ffc8a4aea59307…

MALICIOUS

Office (OLE) / .XLSX

2.61 MB
MD5: 58cbe7516369d9e79660bda6e576cffd SHA-1: 813b0fbabba6f9ad23ee2f247312ba29b2e4b16d SHA-256: d3ffc8a4aea59307e4109a293a2ce368e89a816ceb1c1dcb8c5ff35f3cb81e15
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing

The sample is an encrypted Office XLSX file that contains an embedded Equation Editor OLE object. Heuristics indicate this object is likely an exploit carrier for CVE-2018-0798, designed to execute a payload. The document's encrypted nature and the specific exploit vector suggest a phishing or social engineering attack aimed at delivering a malicious payload. No specific family could be identified, and no direct IOCs like URLs or hashes were extracted from the file's content.

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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