Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 994b4f5d2145b0c6…

MALICIOUS

RTF / .DOC

1.99 MB
MD5: 4b36f4e19697762443b8074ce4295170 SHA-1: 7e4eab296c417846c55c08236c1dda1d06591873 SHA-256: 994b4f5d2145b0c6d7ae88d1d5a94b528a00c7c7d193ca3fd073593697c89ad0
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains multiple indicators of malicious activity, including embedded OLE objects and excessive hex-encoded data. Specifically, the RTF_EQUATION_EDITOR and CVE_2017_11882_RELATED heuristics indicate the exploitation of the Equation Editor vulnerability (CVE-2017-11882). The extasciitilde 1MB decoded OLE object likely contains the second-stage payload. The RTF_OBJUPDATE heuristic suggests that the embedded object is designed to be automatically activated upon opening.

Heuristics 5

  • 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.
  • \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 ~2081KB 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_off00000089.bin
f0044c12bb7fd8aefeac0b82c1eeca0e279db945f59304f66c3d97e8efd360b3		 rtf-objdata-decoded RTF \objdata at offset 0x89 1040713 bytes

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