Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f4b9e3f15d14bb71…

MALICIOUS

RTF / .DOC

26.1 KB First seen: 2022-11-08
MD5: be0d3617e56cdb51e7ebade7d47cca95 SHA-1: c47ed3cbdcdfa0617df72d31c932d46b0ae9314c SHA-256: f4b9e3f15d14bb714c4119e8168f2e1381047b65a3ca67407d47c093db166324
220 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic T1559.001 Component Object Model Hijacking: Component Object Model

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability in the Equation Editor component. This vulnerability allows for the execution of arbitrary code when the OLE object is activated, which is triggered by the \objupdate directive. The document also contains a lure instructing the user to 'Enable editing', a common tactic to bypass security measures and 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_off00005270.bin
ba38e4f24d8affa10cfb5a600ecae2482f536e73b6dafc5d2b1e62f703e8309c		 rtf-objdata-decoded RTF \objdata at offset 0x5270 1596 bytes

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