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

Static analysis result for SHA-256 e33f112d4919ecd3…

MALICIOUS

Office (OLE) / .XLSX

1.30 MB
MD5: c5e80b43aef05c959f6c225d572ea833 SHA-1: b911ebeb9803cda95b4f3ab7607fd6a000a2b7a2 SHA-256: e33f112d4919ecd3f1541526b3b3dcf63afa140fac2cac7b9d9a9a084d153e3c
140 Risk Score

Malware Insights

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

The sample is an OOXML file encrypted with a default password, indicating it's likely an exploit carrier. High-severity heuristics indicate the presence of an Equation Editor OLE object (OLE_EQUATION_EDITOR) which contains a payload-like Ole10Native stream (OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY). This strongly suggests the file is designed to exploit a vulnerability within the Equation Editor to execute a malicious payload, likely delivered as a spearphishing attachment.

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.