Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5f37bb3fc842b02d…

MALICIOUS

RTF / .DOC

16.8 KB
MD5: cf95e30ae7ca9cbc2916ee16162c7d4a SHA-1: 17e32ec761ebd87995d7d122fba4fc5fb47efdd6 SHA-256: 5f37bb3fc842b02d5945229b345878efe39652dd97acd62ff7cd6a50b18535fb
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE object data and specifically triggers heuristics related to Equation Editor and CVE-2017-11882. This indicates the file is designed to exploit this vulnerability for client-side execution. The presence of ".objupdate" further suggests an attempt to force OLE activation. Without a document body or scripts, the exact payload is unknown, but the exploit mechanism is clear.

Heuristics 5

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger 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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000104e.bin
4c4c63683b927368ac2a6d5dd0b6222b296788e81651a8f7c19426e1aaeb87a2		 rtf-objdata-decoded RTF \objdata at offset 0x104E 1720 bytes

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