Malicious RTF — malware analysis report

Static analysis result for SHA-256 e0109d225048b5c6…

MALICIOUS

RTF

15.6 KB First seen: 2022-12-07
MD5: 1b1b561d94a56c13c1f1655fa203a8e9 SHA-1: 90282a21f60a98eb13343c75f3e38ec34d1369d9 SHA-256: e0109d225048b5c69492c334a310a26968c00a863e85b1b14f52b6ddcc566238
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for arbitrary code execution upon opening the document. The decoded object data suggests an attempt to execute a payload, likely a second-stage downloader or shellcode.

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 1 \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_off0000135d.bin
e5a34db72eecc7f7f3b9250a1d9217cd6923cb0873d9b6b94e08d6f8803a74cc		 rtf-objdata-decoded RTF \objdata at offset 0x135D 1679 bytes

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