Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5f5f4e0ab65f657f…

MALICIOUS

RTF / .DOC

24.6 KB First seen: 2022-11-21
MD5: 45fb8c89e503e86d0078c03305723aca SHA-1: 26098f3510983f3cffb6d86d861003ef8f88294c SHA-256: 5f5f4e0ab65f657ff487ef5e7f60c1d95e48957a1228838974aface195a0d30e
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains an embedded OLE object specifically targeting 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. The `SE_ENABLE_LURE` heuristic suggests the document prompts the user to enable content, a common social engineering tactic to facilitate the exploit.

Heuristics 6

  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000043ac.bin
25027d5f95ff22a4f2bfdee2127d980cc520bc1af80bb1ccaeb994bcab266363		 rtf-objdata-decoded RTF \objdata at offset 0x43AC 1706 bytes

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