Malicious RTF — malware analysis report

Static analysis result for SHA-256 e399cdab404d5046…

MALICIOUS

RTF

12.7 KB First seen: 2023-03-03
MD5: ba628c629f3472e3b57de14e3cdb05d2 SHA-1: b492c03cb6824682d575a6b77e3c1c3b7755a331 SHA-256: e399cdab404d5046aba55ff32346f96349d482763a3b1c633c9a8fb594f09a17
120 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566.001 Spearphishing Attachment

The sample is an RTF document that leverages the Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR heuristic. The ".objupdate" directive suggests that the embedded OLE object is designed to be activated automatically, likely to trigger the exploit. The presence of OLE object data further supports this. The ultimate goal appears to be the download and execution of a second-stage payload.

Heuristics 3

  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001395.bin
fa12a020b2a0c9dc54db392fe8e1e74ae658ed611098741590d32671ee6f6895		 rtf-objdata-decoded RTF \objdata at offset 0x1395 1746 bytes

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