Threats Tagged 'web shells'

UAT-8099 is a malware campaign active from August 2025 to early 2026 targeting vulnerable IIS servers, primarily in Asia, with a focus on Thailand and Vietnam. It uses web shells, PowerShell scripts, and the GotoHTTP tool to maintain persistent remote access. New BadIIS malware variants show enhanced persistence, regional customization, and SEO fraud capabilities, with a Linux ELF variant indicating cross-platform targeting. The campaign shares infrastructure with the WEBJACK campaign, suggesting operational overlap. Although no known exploits are reported in the wild, advanced evasion and persistence techniques pose risks to confidentiality, integrity, and availability. European organizations with exposed IIS servers, especially those with business ties to Asia, should be vigilant. Targeted detection of web shells, PowerShell abuse, and monitoring for GotoHTTP traffic are critical mitigations. Germany, France, and the UK are most likely affected due to IIS usage and strategic interests in Asia.

MediumMalwareGermanyFranceNetherlands+5#persistence#web shells#asia

A Chinese-speaking cybercrime group, UAT-8099, is targeting high-value Internet Information Services (IIS) servers for search engine optimization fraud and data theft. The group focuses on reputable servers in India, Thailand, Vietnam, Canada, and Brazil, affecting universities, tech firms, and telecom providers. UAT-8099 uses web shells, hacking tools, Cobalt Strike, and BadIIS malware to manipulate search rankings and maintain persistence. They exploit weak file upload settings, enable guest accounts, and use RDP for access. The group also steals valuable credentials, configuration files, and certificates. New BadIIS variants with low detection rates and Chinese debug strings have been identified. The attackers employ SEO techniques like backlinking and inject malicious JavaScript to redirect users to fraudulent websites.

MediumCampaignGermanyFranceUnited Kingdom+4#chinese-speaking#web shells#data theft

A Chinese-speaking threat actor group, tracked as CL-UNK-1037, has been conducting a large-scale SEO poisoning campaign called Operation Rewrite. The attackers use a malicious IIS module named BadIIS to intercept and alter web traffic on compromised servers, manipulating search engine results to redirect users to malicious sites. The campaign primarily targets East and Southeast Asia, with a focus on Vietnam. The attackers employ various tools including native IIS modules, ASP.NET handlers, and PHP scripts. The operation shows links to previously known threat groups like Group 9 and possibly DragonRank. The campaign demonstrates sophisticated techniques for search result manipulation and traffic redirection, posing significant risks to unsuspecting internet users.

MediumMalwareVietnamChinaSingapore+3#dragonrank#iis module#seo poisoning

A Chinese-speaking threat actor conducted a large-scale SEO poisoning campaign dubbed 'Operation Rewrite' using BadIIS malware to manipulate search results. The attackers compromised legitimate websites and used malicious IIS modules to intercept web traffic and serve altered content. The campaign targeted East and Southeast Asia, particularly Vietnam. Multiple variants of BadIIS were discovered, including ASP.NET handlers and PHP scripts. The threat actor is linked to previously known groups like Group 9 and possibly DragonRank. Their toolkit allowed them to inject malicious content, redirect users, and exploit compromised servers for various malicious purposes.

MediumCampaignGermanyFranceUnited Kingdom+4#badiis#dragonrank#operation rewrite

AhnLab Security Intelligence Center analyzed attacks on Windows web servers during Q2 2025 using their Smart Defense infrastructure. The study focused on poorly managed servers, categorizing attack types and malware strains. It revealed that multiple threat actors often target vulnerable servers simultaneously, exploiting unpatched systems or misconfigurations. Attackers typically use file upload vulnerabilities to deploy web shells and execute commands, but may also exploit framework or Web Application Server weaknesses. The analysis provides detailed statistics on the number of affected systems and the frequency of attacks, offering insights into the current threat landscape for Windows-based web servers.

MediumCampaignGermanyFranceUnited Kingdom+7#iis#wograt#windows

Chinese-speaking threat actors, dubbed UAT-6382, have been exploiting a remote-code-execution vulnerability (CVE-2025-0994) in Cityworks, a popular asset management system. The attacks, which began in January 2025, target local governing bodies in the United States, focusing on utilities management systems. The threat actors deploy various web shells, including AntSword and Chopper, and use custom Rust-based loaders called TetraLoader to deliver Cobalt Strike beacons and VSHell malware. The attackers conduct reconnaissance, enumerate directories, and stage files for exfiltration. Their tooling and tactics indicate a high level of proficiency in the Chinese language, suggesting a Chinese origin for the threat group.

MediumMalwareUnited KingdomGermanyFrance+7#web shells#chinese threat actors#china chopper