JPCERT tracks shifting Mirai-like IoT scanning
JPCERT/CC's TSUBAME sensors show Mirai-like Telnet scanning from Japan declining while non-Mirai botnet traffic from compromised DVRs, NAS and routers rises.
Sourceblogs.jpcert.or.jp — open the original
What to check
- Applies to
- Whether this concerns you is not assessed; the names the report mentions are listed below.
JPCERT/CC's quarterly TSUBAME Internet threat monitoring report for January–March 2026 reviews FY2025 scanning trends observed from sensors in Japan and overseas. The dominant traffic remains scans on 23/TCP (Telnet), long associated with Mirai-family botnets, but the proportion of classic Mirai-like packets fell from roughly 70% at the start of FY2025 to around 30% by year end. In its place, JPCERT/CC observed a rising share of scanning traffic from compromised devices that lack Mirai's characteristic signatures, originating from surveillance cameras, DVRs, NAS devices and broadband routers made by both Japanese and overseas (Korean, Chinese) vendors, with overseas DVR products dominating from October 2025 onward.
The report notes that Mirai-associated source IPs were also seen communicating over non-23/TCP ports, suggesting attackers are pivoting to target specific internet-facing services and known vulnerabilities in particular products rather than relying solely on default Telnet credential brute-forcing. JPCERT/CC shared these findings with domestic device manufacturers and telecom operators to support mitigation and recommends operators harden internet-facing IoT devices, keep firmware updated, and use scanning tools like Shodan to verify no unnecessary services are exposed.
Overall this is a routine quarterly monitoring update rather than a report of new attacks or incidents; JPCERT/CC states no anomaly warranting a special alert was observed this quarter, and 23/TCP and 443/TCP scanning remains widespread across sensors in Japan, North America and Europe.
Mentioned in this report
Source reporting: https://blogs.jpcert.or.jp/en/2026/07/tsubame_overflow_2026-01-03.html
Free public brief. Slack alerts on the vendors you run come with the paid plans, and a new account gets three days of them, no card.
What this brief leaves out
This page is the free tier: the write-up, the severity, the names. In the app the same report carries live profiles of the malware it names. The paid plans add the security research and news reporting the free tier leaves out.
It sits in a corpus of 16,433 reports from 149 sources, 661 of them written in the last seven days, and it grows through the day.
A new account starts with three days of all of it, no card, then keeps the government and CERT reporting free. Slack alerts are a paid-plan feature: name the vendors you run and Slack hears about the reports that touch them, not the rest of the week's. Nothing is charged unless you subscribe.
Create a free account What it costs