Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6431123c8350d26e…

MALICIOUS

RTF / .DOC

18.9 KB
MD5: 29021284714de995a09931f1bb3819a6 SHA-1: 6dd4c4d8f572d0186b8e618e673b19577b7debd3 SHA-256: 6431123c8350d26e97889aede974847d2ee647f2257a97b515589f4c1fa260f8
180 Risk Score

Malware Insights

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

The sample is an RTF document that contains embedded OLE objects, specifically triggering heuristics related to Microsoft Equation Editor and CVE-2017-11882. This indicates the file is designed to exploit this vulnerability for code execution. The presence of ".objdata" and ".objupdate" sections further supports the exploitation of embedded objects. The specific class name "eQUATioN.3" is a strong indicator of this exploit.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • 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.
  • \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_off00001ad3.bin
2e1b61d7f03f565cbc399ed4895633628ec1bdf7b46d056c97f73f4a8a420021		 rtf-objdata-decoded RTF \objdata at offset 0x1AD3 2030 bytes

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