Threats Tagged 'webshell'

Beginning October 7, 2026, threat actors exploited two critical vulnerabilities in AhsayCBS backup utility (CVE-2026-105133 and CVE-2026-105134) to achieve unauthenticated remote code execution on exposed systems. The attackers chained these vulnerabilities together, first bypassing authentication and then executing code with SYSTEM privileges. Post-exploitation activities included deploying JSP webshells, installing XMRig cryptocurrency miners disguised as Microsoft Edge processes, and dropping an AI-assisted PowerShell script that monitors and terminates Task Manager to hide mining operations. The attackers established persistence through a fake Windows service named MicrosoftEdgeUpdateSvc and utilized a vulnerable WinRing0x64.sys kernel driver to enable kernel-level hardware access for optimized mining performance. All AhsayCBS versions through 10.3.4 are affected, with managed service providers being the primary targets.

A threat actor compromised three web servers hosting recreation management software for municipalities and parks organizations by exploiting a file upload vulnerability. After multiple failed exploitation attempts, the attacker registered legitimate accounts and abused the member file upload function to deploy webshells. The attacker enumerated systems, extracted database credentials, and targeted payment card data from Fortis webhook logs. User-agent strings indicate Chinese origin, with suspected AI-generated scripts throughout the operation. The adversary adapted tactics across compromises, employing timestomping and file masquerading for defense evasion. When one server returned to production prematurely, the attacker injected a trojanized jQuery file into authentication pages, establishing WebRTC and WebSocket channels for credential harvesting via Cloudflare Workers infrastructure.

An unauthenticated attacker can chain two WordPress Core vulnerabilities, CVE-2026-63030 and CVE-2026-60137, to achieve remote code execution against affected WordPress installations. Multiple security firms have confirmed active in-the-wild exploitation within days of public disclosure, and public proof-of-concept exploits are circulating. Key takeaways: Two WordPress Core vulnerabilities, CVE-2026-63030 and CVE-2026-60137, can be chained together to achieve pre-authentication remote code execution against WordPress 6.9.x and 7.0.x installations. Multiple security firms have confirmed in-the-wild exploitation, with public proof-of-concept exploits appearing within hours of the July 17, 2026 disclosure. Patches are available in WordPress 7.0.2 and 6.9.5; WordPress.org has enabled forced automatic updates across affected supported installations. Background Tenable's Research Special Operations (RSO) team has compiled this blog to answer Frequently Asked Questions (FAQ) regarding wp2shell, two vulnerabilities in WordPress Core that can be chained together to achieve pre-authentication remote code execution. FAQ What is wp2shell? wp2shell is the name given to two vulnerabilities in WordPress Core. When was wp2shell first disclosed? On July 17, 2026, WordPress released security updates addressing the wp2shell vulnerabilities alongside two GitHub Security Advisories. Adam Kues of Searchlight Cyber, who discovered and disclosed CVE-2026-63030, published research on the same day and chose to hold back the technical specifics given the severity of the finding. Searchlight Cyber also launched wp2shell.com , a testing tool that allows administrators to check whether their WordPress installation is vulnerable. On July 20, Searchlight Cyber published a full technical breakdown of the attack chain. What are the vulnerabilities associated with wp2shell? wp2shell is a two-vulnerability exploit chain affecting WordPress Core. CVE Description CVSSv3 CVE-2026-63030 WordPress Core REST API Batch-Route Confusion Remote Code Execution Vulnerability 9.8 CVE-2026-60137 WordPress Core WP_Query author__not_in SQL Injection Vulnerability 5.9 CVE-2026-63030 is a REST API batch-route confusion weakness introduced in WordPress 6.9. CVE-2026-60137 is a SQL injection flaw in the author__not_in parameter of WP_Query , present in WordPress 6.8 and later. When chained on WordPress 6.9.0 through 7.0.1, the two flaws allow an unauthenticated attacker to reach the REST API batch endpoint at /wp-json/batch/v1 and achieve remote code execution. CVE-2026-60137 was discovered and disclosed by security researchers TF1T, dtro, and haongo. CVE-2026-60137 also affects WordPress 6.8.0 through 6.8.5 as a standalone SQL injection issue. Because CVE-2026-63030 was introduced in WordPress 6.9, the full RCE chain is only achievable on 6.9.x and 7.0.x installations. How severe is the wp2shell vulnerability chain? An anonymous, unauthenticated user can execute the chain against a default WordPress installation with no plugins required. No preconditions exist beyond the default WordPress configuration. Cloudflare notes that the vulnerable code path is reached when “a persistent object cache is not in use.” Note: wp2shell targets WordPress Core itself rather than a plugin or theme. All four prior WordPress-related entries in the CISA Known Exploited Vulnerabilities (KEV) catalog involve plugins, not core. Pre-authentication remote code execution in WordPress Core is uncommon. CVE Product Added to KEV Ransomware CVE-2026-41940 WebPros cPanel & WHM and WP2 (WordPress Squared) April 30, 2026 Known CVE-2020-25213 WordPress File Manager Plugin November 3, 2021 Unknown CVE-2020-11738 WordPress Snap Creek Duplicator Plugin November 3, 2021 Unknown CVE-2019-9978 WordPress Social Warfare Plugin November 3, 2021 Unknown How widespread are the attacks exploiting wp2shell? WordPress is the most widely deployed content management system in the world. Some hosted installations will receive patc…

In June 2026, infrastructure pivoting from TencShell C2 nodes revealed an active intrusion campaign utilizing AI language models for attack automation. Thirteen Hong Kong-based servers across four ASNs exposed an open directory containing victim source code, custom exploits, operational logs, and cloned login pages with notes in Simplified Chinese. The operation employed Claude Code for execution and DeepSeek-v4-pro for attack logic, targeting government systems in Afghanistan, Thailand, and Taiwan, along with reconnaissance against U.S. government portals. The campaign also pursued financial services firms across Europe, Australia, and Asia. Attackers deployed TencShell implants, webshells, and custom exploits including SQL injection and Laravel deserialization attacks, successfully compromising administrative systems and exfiltrating sensitive data including citizen complaints and government employee information.

MediumMalwareUnited StatesAfghanistanTaiwan+2#phishing#vshell#gshell

Two critical zero-day vulnerabilities in NetScaler ADC and Gateway systems are being actively exploited in the wild. CVE-2026-88771 is a remote code execution vulnerability allowing unauthenticated command injection, while CVE-2026-88772 is a DTLS memory overflow flaw enabling RCE or DoS attacks. Threat actors deployed webshells through these vulnerabilities to establish initial access and persistence. The CVE-2026-88771 exploitation involves a three-stage command injection chain poisoning log files, while CVE-2026-88772 exploitation drops .deb webshell files. Attackers used PHP webshells with RC4 encryption for command and control communications, targeting custom directories within NetScaler Gateway interfaces. Cortex Xpanse identified over 50,000 potentially vulnerable exposed instances.

HighVulnerabilityUnited StatesSouth KoreaIndia+10#cve#cve-2025-21042#cwe-787

A malicious cyber actor exploited a Citrix NetScaler Gateway zero-day vulnerability on September 24, 2026, three days before public disclosure. The attacker, using IP address 149.104.78.141, attempted exploitation that was detected through behavioral analysis despite no CVE-specific signatures existing at the time. The exploitation chain aimed to establish persistence through a password-protected webshell, attempting to set setuid and setgid bits on /bin/sh for root access. The attacker tried to configure the web server to execute a hidden PHP webshell disguised as a CSS file, using aliases to route requests. Though unsuccessful in compromising the targeted sensor, the post-exploitation playbook revealed sophisticated techniques for maintaining access and evading detection through web server manipulation.

The Mimo intrusion set is exploiting CVE-2024-46483, a Remote Code Execution vulnerability in Craft CMS, to deploy webshells and execute malicious payloads. The attack chain includes downloading infection scripts and deploying a loader, cryptominer (XMRig), and residential proxyware (IPRoyal) for financial gain. The group uses unique identifiers such as '4l4md4r' and 'n1tr0' and has been linked to operators 'EtxArny' and 'N1tr0'. Detection can focus on unusual processes in temporary directories and kernel module changes. The campaign targets Craft CMS installations globally, with a focus on financially motivated exploitation rather than geopolitical objectives. The threat is medium severity due to the impact on confidentiality and availability, ease of exploitation via RCE, and the scope of affected web servers. Organizations using Craft CMS should prioritize patching and monitoring for indicators of compromise.

MediumMalwareGermanyFranceNetherlands+10#residential proxy#xmrig#cryptomining