RTF malware analysis — malicious · db893460bbf88307

MALICIOUS

RTF

631.3 KB First seen: 2019-04-17

MD5: 32a3a584516f0d4e3843d46054a536f9 SHA-1: 82bfac05c465883b937b54714757fe0c7864f6ff SHA-256: db893460bbf88307ac8e68ea06c672b77260019ad7017e23072b3c4fd98b51ab

340 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The RTF file contains OLE object data and triggers the CVE-2017-8570 vulnerability, which is known to drop SCT scripts. ClamAV identifies the file as Win.Malware.Nemesis-7647563-0, indicating it's a known malware variant. The exploitation likely leads to the execution of a malicious script, which in turn downloads and executes a further stage payload.

Heuristics 7

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.Trojan.Myxah-7541011-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Win.Trojan.Myxah-7541011-0
\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 5 \objdata section(s) — embedded OLE objects
Embedded OLE object medium RTF_OBJEMB

RTF contains \objemb — embedded OLE object

Extracted artifacts 5

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000025.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x25	297689 bytes
SHA-256: `d3abc916a5993863a8f30b9fa57c157ff17830878b1ebb63e020c419d4237ee0`
Detection ClamAV: Win.Trojan.Myxah-7541011-0 Obfuscation or payload: likely Carved artifact entropy is 8.00, consistent with packed or encrypted content.
`objdata_01_off0009b154.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x9B154	1056 bytes
SHA-256: `38e0a590df7eaa9868af736886281809be3c0fe6a6a6ea4e0327baa813cb5642`
`objdata_02_off0009b9d0.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x9B9D0	429 bytes
SHA-256: `c861ab3ab7d28ef7b028a69afbbfc89c1f5c98f0be9f15b26f0565b7d5605703`
`objdata_03_off0009bd66.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x9BD66	1351 bytes
SHA-256: `fbfe6031f946bf25c25f9783662a0516de4f34007dcfe7ff53f2b540dbc1df3f`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): cscript //nologo %vbs%
`objdata_04_off0009c872.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x9C872	2633 bytes
SHA-256: `1f8de175e345e5b9624b8bb5f76e9d4c1d78de3a7bbc2750e8ea7def36f04cfb`

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