Malicious RTF — malware analysis report

Static analysis result for SHA-256 fa2f11300e668311…

MALICIOUS

RTF

19.6 KB First seen: 2020-07-02
MD5: 5a71320db6de64050d7a6a4628825971 SHA-1: 8009f1c63cae798985b0c5699181559cc012ca53 SHA-256: fa2f11300e6683115f030dc34b9c045d43ccf2debc5cd59af2bea14cd0794ce3
120 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object with a split Equation Editor ProgID, indicating exploitation of a known vulnerability (CVE-2017-11882). The ".objupdate" directive forces the activation of this object, which is a common technique for executing arbitrary code. This likely serves to download and execute a secondary payload, although no specific URLs or scripts were extracted to confirm this.

Heuristics 3

  • Split hex Equation Editor ProgID + OLE object critical CVE likely 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 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001098.bin rtf-objdata-decoded RTF \objdata at offset 0x1098 1603 bytes
SHA-256: f9a5561eb52bacf78f6774226a1f33bcd4ca6b01d848ef3a62ea8269f16c3db3

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