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JPCERT/CC reported that 23/TCP remained the most frequently targeted destination in TSUBAME internet monitoring data, but the share of traffic with Mirai-like characteristics fell from about 70% at the start of FY2025 to roughly 30% by the end of the fiscal year. The organization said overseas sensors received more packets than domestic sensors, while some sensors recorded heavier activity on 443/TCP, indicating attackers were not limited to traditional Telnet-focused probing.
From June 2025 onward, JPCERT/CC observed increased non-Mirai-like scanning from compromised IoT devices including surveillance cameras, DVRs, NAS devices, broadband routers, Korean-made DVRs, and Chinese-made routers. It also found that Mirai-like sources were communicating over ports beyond 23/TCP, suggesting attempts to reach internet-exposed services and exploit known product vulnerabilities; JPCERT/CC said it shared the trend data with domestic product developers and telecommunications operators and urged firmware updates, secure configuration, and exposure checks such as port scans or SHODAN searches.
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On 2026-01-03, JPCERT/CC published its TSUBAME Report Overflow for January to March 2026, summarizing FY2025 Japan-related monitoring trends. The report said scans targeting 23/TCP remained most common, Mirai-like traffic from Japan declined over FY2025, and some Mirai-like sources were communicating over ports beyond 23/TCP.
From June 2025 onward, JPCERT/CC observed increased scanning from compromised IoT devices whose traffic did not match Mirai-like characteristics. The devices included surveillance cameras, DVRs, NAS devices, broadband routers, Korean-made DVRs, and Chinese-made routers.
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JPCERT/CC's TSUBAME sensors detected a sharp increase in Mirai-like traffic targeting Telnet (`TCP/23`) beginning April 30 and peaking in early May. Source addresses were globally distributed, led by the United States, with substantial increases from Germany, France, Canada, and Japan; Japanese-origin activity rose to roughly 15 times its pre-surge baseline. Many source hosts were associated with hosting providers and exposed cPanel administration interfaces. The activity may be associated with exploitation of **CVE-2026-41940**, an authentication-bypass flaw in cPanel/WHM, followed by Mirai or variant infections, although the sensor data does not establish causation. `TCP/23` was the most targeted port across domestic and overseas sensors during April–June, alongside broad scanning of `TCP/443`, `TCP/80`, `TCP/8080`, and `TCP/22`. Organizations should promptly patch exposed cPanel/WHM systems, restrict remote administration access, enforce strong credentials, and investigate anomalous processes and outbound network activity, as Mirai variants can compromise internet-facing servers as well as IoT devices.
Sep 18, 2026
A renewed **Mirai** botnet campaign is targeting internet-exposed routers and IoT devices by exploiting known vulnerabilities, with advisories highlighting compromises affecting industrial routers, smart home systems, DVRs, cameras, and 5G/LTE equipment. Reported targets include devices from **ASUS, Huawei, Neterbit, LB-Link, Four-Faith, Kguard, Lilin,** and **Vimar**, as well as generic DVR platforms and PZT cameras, indicating broad opportunistic scanning of exposed edge infrastructure. National CERT advisories from Brunei and Colombia warned that Mirai-related botnet activity continues to threaten consumer and industrial environments, including routers and other connected devices. Defenders were urged to **patch exposed systems**, **disable remote access where possible**, **replace default credentials with strong unique passwords**, and **scan networks for vulnerable or internet-facing assets** to reduce the risk of botnet enrollment and downstream abuse such as distributed denial-of-service activity.
Aug 1, 2026
Mirai-related botnets remained highly active as operators rapidly incorporated newly disclosed remote code execution flaws and weak-credential attacks against internet-facing IoT and network security devices. Palo Alto Networks Unit 42 reported an active campaign exploiting vulnerabilities including `CVE-2021-27561`, `CVE-2021-27562`, `CVE-2021-22502`, and `CVE-2020-26919` across products such as SonicWall SSL-VPN, D-Link DNS-320, Yealink Device Management, Micro Focus Operation Bridge Reporter, Netis routers, and Netgear ProSAFE Plus devices. Fortinet likewise observed roughly 200 attacks per day in a three-week honeypot study, with nearly 4,000 of about 4,700 Telnet attacks tied to Mirai-related malware families and variants quickly adding exploits such as OptiLink GPON RCE, `CVE-2021-1498`, and `CVE-2021-31755`. Successful compromises typically fetched shell scripts that installed multi-architecture Mirai binaries, and in some cases added SSH brute-force and scanning tools, attempted persistence, removed artifacts, and blocked management ports to retain control. Researchers said the broader botnet ecosystem also remained resilient beyond Mirai alone: Fortinet identified active variants including **SORA**, **SYLVEON**, **Hajime**, and **MANGA**, while earlier Netlab 360 analysis showed Hajime continuing to grow through a modular peer-to-peer architecture and propagation via TR-069 flaws and weak Telnet credentials. The combined reporting underscores that unpatched edge devices and default or weak passwords continued to fuel large-scale botnet expansion.
Aug 15, 2026