Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7784da265944f7be…

MALICIOUS

RTF / .DOC

8.7 KB First seen: 2022-10-10
MD5: 61ff33ff58f2b1f62f9ee3c475c3f4e1 SHA-1: 514ea2602a279f98d5a3baa81ffc890714c1a144 SHA-256: 7784da265944f7be2165cb04cb0807694e7baedbc6a32ce039684b0450fa69cd
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The sample is an RTF document that contains an OLE object exploiting the CVE-2017-11882 vulnerability in Microsoft Equation Editor. The document body contains a lure instructing the user to 'Enable editing', which is a common technique to bypass macro security settings and trigger the exploit. The exploit allows for arbitrary code execution, likely to download and run a second-stage payload.

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_off00001050.bin
5fd61f96bc59177f0435386549de1317ca6aa26f2ed53670edd13ef0ccf3ff37		 rtf-objdata-decoded RTF \objdata at offset 0x1050 1340 bytes

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