Rtf.Dropper.Agent-9965975-1 — RTF / .DOC malware analysis

Static analysis result for SHA-256 126c689737fbbd23…

MALICIOUS

RTF / .DOC

1.69 MB First seen: 2023-04-19
MD5: 5cf988bd918846dbedc2f30a6dc1e139 SHA-1: dcdccb69e197cc69cc682288d9f2b94999ce157f SHA-256: 126c689737fbbd239b143e8ea9b6f0c83d0229a48ac3d91ffbb7e5ed0393d8d4
302 Risk Score

Malware Insights

Rtf.Dropper.Agent-9965975-1 · confidence 95%

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

The RTF file contains multiple indicators of exploitation, including OLE object data and specifically the CVE-2017-11882 Equation Editor vulnerability. The presence of a PE header in hex data and ClamAV detection as Rtf.Dropper.Agent-9965975-1 strongly suggest this file is a dropper designed to execute a secondary payload.

Heuristics 8

  • 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.
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • ClamAV: Rtf.Dropper.Agent-9965975-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-9965975-1
  • \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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Suspicious extracted artifact info 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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00080080.bin
686845cff9d46f52cf6681c9df9c2eec20f7b9c5d341679c26aaefde099a81e7		 rtf-objdata-decoded RTF \objdata at offset 0x80080 141856 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.94, consistent with packed or encrypted content.
objdata_01_off000d0232.bin
778f9f0a70e56737c679ea50d4a9598ed2c7ccbf07af21befc64d3d0c4b2e39f		 rtf-objdata-decoded RTF \objdata at offset 0xD0232 187272 bytes

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