WrtHug Exploits Six ASUS WRT Flaws to Hijack Tens of Thousands of EoL Routers Worldwide

A newly discovered campaign has compromised tens of thousands of outdated or end-of-life (EoL) ASUS routers worldwide, predominantly in Taiwan, the U.S., and Russia, to rope them into a massive network.

The router hijacking activity has been codenamed Operation WrtHug by SecurityScorecard’s STRIKE team. Southeast Asia and European countries are some of the other regions where infections have been recorded.

The attacks likely involve the exploitation of six known security flaws in end-of-life ASUS WRT routers to take control of susceptible devices. All the infected routers have been found to share a unique self-signed TLS certificate with an expiration date set for 100 years from April 2022.

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SecurityScorecard said 99% of the services presenting the certificate are ASUS AiCloud, a proprietary service designed to enable access to local storage via the internet.

“It leverages the proprietary AiCloud service with n-day vulnerabilities in order to gain high privileges on End-Of-Life ASUS WRT routers,” the company said in a report shared with The Hacker News, adding the campaign, while not exactly an Operational Relay Box (ORB), bears similarities with other China-linked ORBs and botnet networks.

The attacks likely exploit vulnerabilities tracked as CVE-2023-41345, CVE-2023-41346, CVE-2023-41347, CVE-2023-41348, CVE-2024-12912, and CVE-2025-2492 for proliferation. Interestingly, the exploitation of CVE-2023-39780 has also been linked to another Chinese-origin botnet dubbed AyySSHush (aka ViciousTrap). Two other ORBs that have targeted routers in recent months are LapDogs and PolarEdge.

Out of all the infected devices, seven IP addresses have been flagged for exhibiting signs of compromise associated with both WrtHug and AyySSHush, potentially raising the possibility that the two clusters could be related. That being said, there is no evidence to back this hypothesis beyond the shared vulnerability.

The list of router models targeted in the attacks is below –

• ASUS Wireless Router 4G-AC55U
• ASUS Wireless Router 4G-AC860U
• ASUS Wireless Router DSL-AC68U
• ASUS Wireless Router GT-AC5300
• ASUS Wireless Router GT-AX11000
• ASUS Wireless Router RT-AC1200HP
• ASUS Wireless Router RT-AC1300GPLUS
• ASUS Wireless Router RT-AC1300UHP

It’s currently not clear who is behind the operation, but the extensive targeting of Taiwan and overlaps with previous tactics observed in ORB campaigns from Chinese hacking groups suggest it could be the work of an unknown China-affiliated actor.

“This research highlights the growing trend of malicious threat actors targeting routers and other network devices in mass infection operations,” SecurityScorecard said. “These are commonly (but not exclusively) linked to China Nexus actors, who execute their campaigns in a careful and calculated manner to expand and deepen their global reach.”

“By chaining command injections and authentication bypasses, threat actors have managed to deploy persistent backdoors via SSH, often abusing legitimate router features to ensure their presence survives reboots or firmware updates.”

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