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

Static analysis result for SHA-256 584e4b1e39d3ea6f…

MALICIOUS

Office (OLE) / .XLSX

2.26 MB
MD5: 1bf3426c2e62290e3bdf45e4fd0c4202 SHA-1: adfedc7cea61f2a16d2ba86d3be5c2cff0a01f08 SHA-256: 584e4b1e39d3ea6f25489c39be1bb852fb3ee619924f94a9c8f1908beda6ba0c
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The file is an encrypted Excel spreadsheet that utilizes a default password, a common technique for hiding malicious content. It contains an Equation Editor OLE object, which is frequently exploited. Specifically, the heuristics indicate a high likelihood of exploitation via CVE-2018-0798 due to anomalous Equation Editor native stream properties. The embedded OLE object appears to carry a payload, suggesting it's designed to deliver a secondary exploit or malware.

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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