Malicious RTF — malware analysis report

Static analysis result for SHA-256 707081c82a146112…

MALICIOUS

RTF

3.8 KB
MD5: 385aaf9c783d2306e811c55ce2874946 SHA-1: 40c5e6ee213a4b1e0b9342a28fddaafcb7e32a17 SHA-256: 707081c82a1461124554e247c713cf2591d0df6acc01d554ab8b32bf432e9dfa
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED heuristics strongly indicates exploitation of this known vulnerability for client-side execution. The RTF_OBJUPDATE heuristic further suggests that the embedded object is designed to be activated automatically.

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_off00000092.bin
32b57b9f9fa1f86a09fb382e55ab59ba072195862f2710b2934022c72d8475fa		 rtf-objdata-decoded RTF \objdata at offset 0x92 1742 bytes

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