Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1a656f17d0145cb8…

MALICIOUS

RTF / .DOC

24.9 KB First seen: 2022-11-25
MD5: 12f7492e0b937a3e8eda18950bb84d23 SHA-1: 4d92fd377c76c764057564a2bc208f6db7ec88c2 SHA-256: 1a656f17d0145cb825fb192f30b3ea8a40478bf0225e7d64ff0059bfba7473ab
220 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The document body contains a lure related to marketing strategy, and heuristic firings indicate the presence of an automatically linked OLE object designed to activate upon opening. The 'SE_ENABLE_LURE' heuristic suggests the document instructs the user to enable editing, a common tactic for macro-based malware delivery.

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_off00004cac.bin
f803c7afa632c458ee881a9442fa068b9ed52ac03bc9d5d09b3fd52a77813c96		 rtf-objdata-decoded RTF \objdata at offset 0x4CAC 1674 bytes

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