Malicious RTF — malware analysis report

Static analysis result for SHA-256 5703e505a95adc06…

MALICIOUS

RTF

1.15 MB First seen: 2021-06-17
MD5: d253bf7aae3cfdc363c3264f38b8d8bf SHA-1: f8bd9ea74f4d50769a03ca831266e0ad4264338b SHA-256: 5703e505a95adc06e8c66b97bbbe053f5cf0b9244a608f731def106567e86a26
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple indicators of exploitation, specifically related to CVE-2017-11882 through the Equation Editor. The presence of OLE objects and the explicit firing of the RTF_EQUATION_EDITOR heuristic strongly suggest this vulnerability is being leveraged. The embedded object likely contains shellcode or a payload designed to execute arbitrary code on the victim's system.

Heuristics 6

  • Split hex Equation Editor ProgID + OLE object critical CVE likely 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.
  • 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.
  • \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.
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000f58.bin rtf-objdata-decoded RTF \objdata at offset 0xF58 45687 bytes
SHA-256: df33956952138971ba966d678e80bed1d5d5d3c0d3f00b58dfaae6ac51c04c9e
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): Wscript.ScriptFullName
objdata_01_off00029078.bin rtf-objdata-decoded RTF \objdata at offset 0x29078 254403 bytes
SHA-256: 20c4e2a77ad61ec6e1507bc36bd527a5e7c369d4e500da5621981815b301c256

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