Summary (Bottom Line Up Front)
External threat actor from Bangladesh (203.76.96.42) conducted SMB protocol reconnaissance including legacy SMBv1 dialect negotiation attempts over a 4-hour window on February 28, 2026. Assessed threat level is MEDIUM with 85% confidence, representing potential precursor to SMB exploitation attempts. Immediate SMB hardening and monitoring recommended.
Activity Timeline
INITIAL REPORT2026-03-17T13:58:35Z
Source: Analyst Manual Entry
External threat actor from Bangladesh (203.76.96.42) conducted SMB protocol reconnaissance including legacy SMBv1 dialect negotiation attempts over a 4-hour window on February 28, 2026. Assessed threat level is MEDIUM with 85% confidence, representing potential precursor to SMB exploitation attempts. Immediate SMB hardening and monitoring recommended.
Technical details
Source IP 203.76.96.42 (AS23688 Link3 Technologies Ltd., Dhaka) generated 24 events targeting SMB services using insecure protocol dialects. Attack employed MITRE technique T1135 (Network Share Discovery) during reconnaissance phase of kill chain. SMB negotiation attempts included vulnerable SMBv1 protocol on non-standard port 9001, indicating potential targeting of misconfigured or legacy SMB implementations. Windows-based attacking system observed with open ports 80 and 4343. Zero-day probability assessed at 5% with unknown threat actor attribution.
IOCs
IP:203.76.96.42
ASN:23688
COUNTRY:BD
Recommendations
- Disable SMBv1 protocol across all Windows systems and network shares immediately
- Implement network segmentation to restrict SMB traffic (ports 445, 139) to authorized internal networks only
- Deploy enhanced monitoring for SMB protocol anomalies and non-standard port usage
- Conduct vulnerability assessment of all SMB-enabled systems for known CVEs and misconfigurations
- Block source IP 203.76.96.42 and monitor for additional reconnaissance from AS23688 address space