RTF malware analysis — malicious · 5dcb3eb1e0b21b58

MALICIOUS

RTF

389.0 KB First seen: 2019-08-04

MD5: 998d5bb977fb2fc3feb2fab7b5982ce9 SHA-1: b7aeb6c6373222cb3f7b3cb60c0753f2eb9304e7 SHA-256: 5dcb3eb1e0b21b58413e55a161b4beb8d86b03367fd7129957356370ab3466ed

344 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The RTF file contains OLE object data and triggers CVE-2017-8570, indicating it's designed to drop and execute a script. The presence of a PE header in hex data and ClamAV detections for Win.Packer.MalwareCrypter-6642003-1 further confirm its malicious nature. The embedded artifact objdata_05_off00006710.bin likely contains the dropped 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.Packer.MalwareCrypter-6642003-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Win.Packer.MalwareCrypter-6642003-1
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 6 \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 6

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	870 bytes
SHA-256: `32061a4dca89ef49c09f05d649d9d25dda979cbf0f2da90d4c3523ad7b48cca2`
`objdata_04_off00005236.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x5236	2633 bytes
SHA-256: `fe11c27d916ab897eb94064e9631d8a29c847a6db39259bef31578da8d19fdf5`
`objdata_05_off00006710.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x6710	185980 bytes
SHA-256: `b82d244e7a213097dd2dbf4080b475f5e222db9943182855e069b698c24c9b3c`
Detection ClamAV: Win.Packer.MalwareCrypter-6642003-1 Obfuscation or payload: likely Carved artifact entropy is 7.88, consistent with packed or encrypted content.

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