Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 4f0733b7cecab8f1…

MALICIOUS

RTF / .DOC

1.70 MB
MD5: fd8874bb5296a7c58021530e1ff050c6 SHA-1: c2559f431ece776a5fd0af5fa5fb361a02a058ff SHA-256: 4f0733b7cecab8f13c2ec1f4519a93de10dcf51f32f1aa2a0b17687206092a9f
260 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment T1059 Command and Scripting Interpreter

The sample is an RTF document containing OLE object data, specifically triggering critical heuristics for Equation Editor and CVE-2017-11882. This indicates the document is designed to exploit this known vulnerability. The presence of large amounts of hex-encoded data within the OLE object suggests it is used to hide a malicious payload. The exploit likely leads to the download and execution of a second-stage payload.

Heuristics 6

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1776KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001432.bin
ae36d2e55d16f5b672e3d3e88ee4f6276f18b016278ce8552f95ec18baf34bf8		 rtf-objdata-decoded RTF \objdata at offset 0x1432 888337 bytes

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