Malicious RTF — malware analysis report

Static analysis result for SHA-256 afd9876dd2fe328e…

MALICIOUS

RTF

638.5 KB First seen: 2019-04-18
MD5: 65dec17313d07fbd5f419acaceea2485 SHA-1: d3412535fba08885056f60ac633b091a46883fdb SHA-256: afd9876dd2fe328eaf72a0bec2011ce33b0e93be1712d05fa32a5ee2e6dd718d
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.Malware.Fareit-6753003-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Malware.Fareit-6753003-0
  • \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.

FilenameKindSourceSize
objdata_00_off00000025.bin rtf-objdata-decoded RTF \objdata at offset 0x25 310031 bytes
SHA-256: 596c8769f09c0c8e3e71714d3571b392485ed698aac82ba2e50a3bf7d5c6c7cc
Detection
ClamAV: Win.Malware.Fareit-6753003-0
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.
objdata_01_off0009ce4f.bin rtf-objdata-decoded RTF \objdata at offset 0x9CE4F 1056 bytes
SHA-256: 38e0a590df7eaa9868af736886281809be3c0fe6a6a6ea4e0327baa813cb5642
objdata_02_off0009d6c5.bin rtf-objdata-decoded RTF \objdata at offset 0x9D6C5 429 bytes
SHA-256: c861ab3ab7d28ef7b028a69afbbfc89c1f5c98f0be9f15b26f0565b7d5605703
objdata_03_off0009da53.bin rtf-objdata-decoded RTF \objdata at offset 0x9DA53 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_off0009e548.bin rtf-objdata-decoded RTF \objdata at offset 0x9E548 2633 bytes
SHA-256: 8b52b981393201c0306debe097c2c356eb54ab68ce0bdbf8cf42fe0426e2aa24