RTF malware analysis — malicious · f3c8257c632dc509

MALICIOUS

RTF

349.6 KB First seen: 2019-05-10

MD5: a3e11b9f069741b84492fa4cf722b419 SHA-1: 618bf9d4c58c25f56440130ec889ce8ad28821dc SHA-256: f3c8257c632dc509170672eabda1d71f86f8596529f91cb477961528be4a9d29

344 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The RTF file contains multiple indicators of malicious activity, including OLE object data, a composite moniker, and a PE header within hex data. Crucially, it exploits CVE-2017-8570, which is known to drop a script file. An extracted artifact, objdata_05_off00006688.bin, is also flagged as suspicious and likely contains the second-stage payload.

Heuristics 8

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.
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: Win.Dropper.Gandcrab-7077551-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Win.Dropper.Gandcrab-7077551-0
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 8 \objdata section(s) — embedded OLE objects
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 7

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00003af4.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x3AF4	885 bytes
SHA-256: `eeabec211f2ccdc2d7c9de123e145457e6ea1837722e08b7b8d755219cd5056e`
`objdata_01_off00004211.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x4211	612 bytes
SHA-256: `c62851521e10316dfd43f2b6ee67cc27e2a24456bb346c8fa9dc4a6d6e21d526`
`objdata_02_off0000470b.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x470B	482 bytes
SHA-256: `8f35162cb7523f92e9f44d62d12eded23d00d10857cb163693e107bc76bbe0d8`
`objdata_03_off00004b03.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x4B03	850 bytes
SHA-256: `f4d52089bdd4e315fef23608700d3284f76fb6b468ae29aa8a1c54a5ef0a4a01`
`objdata_04_off0000520e.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x520E	2633 bytes
SHA-256: `fe11c27d916ab897eb94064e9631d8a29c847a6db39259bef31578da8d19fdf5`
`objdata_05_off0000670b.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x670B	2601 bytes
SHA-256: `67ff079a9b0f053ca2843811d9da7a8fdedc7d9d377ef39d09dde148b9657c7f`
`objdata_06_off00007ba9.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x7BA9	163132 bytes
SHA-256: `bece05f72549b82706362366e1e1541034b22e07b164e989e686597bb4aa4c3f`
Detection ClamAV: Win.Dropper.Gandcrab-7077551-0 Obfuscation or payload: likely Carved artifact entropy is 7.84, consistent with packed or encrypted content.

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