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GhostRedirector Campaign Targets Windows Servers with Rungan Backdoor and Gamshen IIS Module

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3 unique sources, 8 articles

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The GhostRedirector threat cluster, also known as Operation Rewrite and CL-UNK-1037, has compromised at least 65 Windows servers in Brazil, Thailand, and Vietnam, deploying the Rungan backdoor and Gamshen IIS module. The campaign, active since at least March 2025, targets various sectors and uses SEO fraud to manipulate search engine results, particularly to boost the rankings of gambling websites. The threat actor, believed to be China-aligned, employs BadIIS, a malicious native IIS module, to intercept and modify HTTP traffic, serving malicious content to site visitors. The campaign also deploys other tools for remote access, privilege escalation, and information gathering. The UAT-8099 group, similar to GhostRedirector, hijacks IIS servers to funnel mobile search engine traffic to spam advertisements and illegal gambling websites. The group targets servers in Brazil, Canada, India, Thailand, and Vietnam, using open-source web shells for initial access and privilege escalation. UAT-8099 installs the BadIIS module to intercept and manipulate HTTP traffic for SEO poisoning and malicious redirects. The attackers use BadIIS to serve SEO terms to search engine crawlers and redirect human visitors to scam websites. UAT-8099 deploys a Cobalt Strike backdoor to maintain persistent access and exfiltrate sensitive data. The group's activities are often undetected by the targeted organizations due to the stealthy nature of the attacks. Cisco Talos has detailed the full attack chain and additional findings relating to the UAT-8099 campaign, identifying several new BadIIS malware samples with altered code structures to evade detection. The group uses SoftEther VPN, EasyTier, and the FRP reverse proxy tool for persistence and deploys defense mechanisms to secure their foothold. The UAT-8099 group was first discovered in April 2025 and primarily targets mobile users, including both Android and Apple iPhone devices. The group uses the Everything tool to search for valuable data within compromised hosts. BadIIS operates in three modes: Proxy, Injector, and SEO fraud. BadIIS uses backlinking to boost website visibility and rankings. The latest campaign by UAT-8099, discovered by Cisco Talos, targets IIS servers in India, Pakistan, Thailand, Vietnam, and Japan, with a focus on Thailand and Vietnam. The group uses web shells and PowerShell to deploy the GotoHTTP tool for remote access. The campaign involves deploying tools like Sharp4RemoveLog, CnCrypt Protect, OpenArk64, and GotoHTTP. UAT-8099 creates hidden user accounts named 'admin$' and 'mysql$' to maintain access. BadIIS malware variants include BadIIS IISHijack and BadIIS asdSearchEngine, targeting specific regions. BadIIS asdSearchEngine has three variants: Exclusive multiple extensions, Load HTML templates, and Dynamic page extension/directory index. UAT-8099 is refining its Linux version of BadIIS, targeting Google, Microsoft Bing, and Yahoo! crawlers.

Timeline

  1. 04.09.2025 20:58 8 articles · 4mo ago

    GhostRedirector Campaign Compromises 65 Windows Servers with Rungan and Gamshen

    The group targets organizations such as universities, tech firms, and telecom providers. The majority of targets are mobile users, including both Android and Apple iPhone devices. The group uses SoftEther VPN, EasyTier, and the FRP reverse proxy tool for persistence. Cisco Talos identified several new BadIIS malware samples in the campaign. The new BadIIS variants have an altered code structure and functional workflow to evade detection. The group deploys defense mechanisms to prevent other threat actors from compromising the same server. The UAT-8099 group was first discovered in April 2025. The group primarily targets mobile users, including both Android and Apple iPhone devices. The group uses the Everything tool to search for valuable data within compromised hosts. BadIIS operates in three modes: Proxy, Injector, and SEO fraud. BadIIS uses backlinking to boost website visibility and rankings. The latest campaign by UAT-8099, discovered by Cisco Talos, targets IIS servers in India, Pakistan, Thailand, Vietnam, and Japan, with a focus on Thailand and Vietnam. The group uses web shells and PowerShell to deploy the GotoHTTP tool for remote access. The campaign involves deploying tools like Sharp4RemoveLog, CnCrypt Protect, OpenArk64, and GotoHTTP. UAT-8099 creates hidden user accounts named 'admin$' and 'mysql$' to maintain access. BadIIS malware variants include BadIIS IISHijack and BadIIS asdSearchEngine, targeting specific regions. BadIIS asdSearchEngine has three variants: Exclusive multiple extensions, Load HTML templates, and Dynamic page extension/directory index. UAT-8099 is refining its Linux version of BadIIS, targeting Google, Microsoft Bing, and Yahoo! crawlers.

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