Malicious RTF — malware analysis report

Static analysis result for SHA-256 4472279d196ee202…

MALICIOUS

RTF

42.8 KB First seen: 2022-12-19
MD5: 7fa7fe9b2f56b8d4cbca426bebac8774 SHA-1: 94b86bd27c928ef1da1bce1c5b606809ccf87a73 SHA-256: 4472279d196ee2021aa4a86afd7cee7c02caf3f1717dc196b5b60a67a21c19f0
200 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object specifically identified as related to CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. The presence of \objupdate and the ProgID 'EQUaTiON.3' strongly indicate an attempt to exploit this vulnerability. The document body's lure to 'Enable editing' further supports the malicious intent, aiming to trick the user into activating 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.
  • \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_off00008c9c.bin
cf1ac8879f6349fbdbe65527bab9e920a8c8f5b479b9a4d1d977a9f782d7e91f		 rtf-objdata-decoded RTF \objdata at offset 0x8C9C 1729 bytes

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