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

Static analysis result for SHA-256 792dfd591d74cfe3…

MALICIOUS

Office (OLE) / .XLSX

1.34 MB
MD5: a88e93c8b1f4cf84bff50aace1293810 SHA-1: 2a2b9dbcf0287e6904e438b7e79ed1c1956e5a7a SHA-256: 792dfd591d74cfe331e0db76a181b02a3aa08c43bfad4512251a8214ba3dd1be
140 Risk Score

Malware Insights

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

The sample is an encrypted Office XLSX file. High-severity heuristics indicate the presence of an Equation Editor OLE object that carries an unusually large Ole10Native stream, a strong indicator of an exploit carrier. The default password encryption further supports its malicious nature. While no specific family is identified, the techniques suggest a delivery mechanism for a secondary payload.

Heuristics 4

  • 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.
  • 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.