Malicious RTF — malware analysis report

Static analysis result for SHA-256 15fb87314ec2c698…

MALICIOUS

RTF

1.12 MB Created: 2020-03-31 22:37:00 First seen: 2020-06-01
MD5: 6ceeacdbf7e009acb3c29c487169c276 SHA-1: 3c5b1dc62f2f85520091fac4fe55a23dcc5314e9 SHA-256: 15fb87314ec2c698dda24155f8cb6d2d9350328515203bba2e12fcdbcb018643
182 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 triggers heuristics related to Equation Editor exploitation, specifically CVE-2017-11882. This indicates the file is designed to exploit a vulnerability in the Equation Editor component to achieve code execution upon opening. No specific family could be identified, but the exploit vector is clear.

Heuristics 6

  • 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 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml In RTF body

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000071a2.bin rtf-objdata-decoded RTF \objdata at offset 0x71A2 118042 bytes
SHA-256: d08277e6523b83b366841c15c508cfc7a0fe04a5e9b8c7920a21ea07e1436c6c

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