Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1747de15fc42dd43…

MALICIOUS

RTF / .DOC

14.3 KB First seen: 2022-10-03
MD5: 482e76553ab58c4cb5f634032c3349f3 SHA-1: bfe44a8dfe88633d03157ff80d905e8084614a18 SHA-256: 1747de15fc42dd43f0e718b213f649fbef77772c4b54254ffa7e6ce9a2822ea7
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 PowerShell T1204.002 Malicious File

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` heuristics strongly indicates exploitation of this specific flaw. The `SE_ENABLE_LURE` heuristic suggests the document prompts the user to enable content, a common social engineering tactic to bypass security measures and facilitate the exploit's execution.

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.
  • \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
  • 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_off000012b0.bin
3676154708348b5a4200f699c8a410adffe4324983c998901280b22ddce309de		 rtf-objdata-decoded RTF \objdata at offset 0x12B0 1790 bytes

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