Malicious RTF — malware analysis report

Static analysis result for SHA-256 e09e2133513b6831…

MALICIOUS

RTF

24.4 KB First seen: 2022-11-23
MD5: 9840b28dccdefdd60cded7e28c82dea9 SHA-1: b0f8d8b2938d929beab034795597fff5f4dac137 SHA-256: e09e2133513b68311b4e451245b5a705bd520e30225af926d6a9d45229c7d2f7
200 Risk Score

Malware Insights

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

The RTF document 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 Equation Editor ProgID strongly indicate exploitation of this vulnerability. The document also contains a lure instructing the user to 'Enable editing', a common tactic to bypass security measures and facilitate the execution of malicious code.

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_off00004722.bin
03cb0979793190d608632a8cddea1e51c478318571ffbef23cdf2d6a111fb604		 rtf-objdata-decoded RTF \objdata at offset 0x4722 1478 bytes

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