RTF malware analysis — malicious · c3e802c8a2f28614

MALICIOUS

RTF

638.1 KB First seen: 2019-05-16

MD5: 6a3cd4aab85ff7b0c1ceb63ec52576b6 SHA-1: 566154dadb304019a8b035d883c9e32ca95cd64e SHA-256: c3e802c8a2f286145c971617e2822a93178b9302acd3c249e8b72968e332bb0c

364 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The sample is an RTF document that leverages OLE objects and a Composite Moniker to exploit CVE-2017-8570. This vulnerability allows the RTF file to drop and execute a second-stage payload, likely an SCT script, which is then executed by the system. The presence of the Equation Editor CLSID and the objdata sections further indicate the exploitation of known RTF vulnerabilities for arbitrary code execution.

Heuristics 10

Composite Moniker — CVE-2017-8570 (drops SCT script) critical CVE related CVE_2017_8570

RTF \objdata decodes to OLE data containing the Composite Moniker — CVE-2017-8570 (drops SCT script) CLSID — the vulnerable control/moniker is embedded directly in the document's object stream, the delivery shape of this exploit. RTF objects auto-render when Word opens the file.
Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR

Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED

RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
ClamAV: Rtf.Dropper.Agent-9965975-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Dropper.Agent-9965975-1
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
\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 7 \objdata section(s) — embedded OLE objects
OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM

RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.
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.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.

URL http://nsis.sf.net/NSIS_Error In RTF body

Extracted artifacts 6

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000031.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x31	287505 bytes
SHA-256: `39513c5fe2b6516a1207f7852e05f094b91ac19c9acac553b2267c2ce7a4a7e4`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.94, consistent with packed or encrypted content.
`objdata_01_off000956d3.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x956D3	11417 bytes
SHA-256: `5d6cfe4c5d1aa428e7c0f5e3f03a769703c8abf56b2cd296a4c4e881ac0011e7`
`objdata_02_off0009b03d.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x9B03D	382 bytes
SHA-256: `9d6fa4be1a4a694cfee89268078c9efc8705b1a473fbb09a37ceb2d45104e44b`
`objdata_03_off0009b375.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x9B375	789 bytes
SHA-256: `8ab026a3e66d94feae5647d5ac6558412271b58006835755f301bcce43b1e52a`
`objdata_04_off0009ba1d.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x9BA1D	2633 bytes
SHA-256: `1feb5f150bb35566d1a01fc59a357dc0ea34bc7498e0ec99bd939f6f848044b0`
`objdata_05_off0009cf45.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x9CF45	4679 bytes
SHA-256: `6bb172535cccd16de71bca846e2bb6df177c56b3a545d6e6314435eabf5d2217`

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