In October 2026, Citrix NetScaler ADC appliances running affected 14.1 builds were compromised through a chain of two vulnerabilities: CVE-2026-88771 and CVE-2026-88779. Attackers achieved root code execution by exploiting a pre-authentication log-poisoning/RCE vulnerability and a SAML-parsing crash. The intrusion involved deploying PHP web shells, modifying system shells, creating cron jobs, and establishing boot hooks for persistence. Additional tools included TCP session managers, HTTP tunnels, and reverse agents for command-and-control. Attackers used a Go-based reconnaissance tool to map internal infrastructure and synchronized implants across appliance pairs to maintain persistence. The campaign exfiltrated NetScaler configurations, historical data, and key material, evolving from initial access to a persistent internal reconnaissance platform.
On August 31, 2026, threat actors exploited two zero-day vulnerabilities in PaperCut MF version 24.0.2, targeting an internet-facing print server in the Education sector. The attackers deployed an in-memory Java loader to establish a web shell, through which they delivered a trojanized Microsoft Copilot binary containing an AdaptixC2 implant. This implant connected to command-and-control infrastructure hosted on Alibaba servers. After a dormant period, the attackers performed reconnaissance and Active Directory enumeration, stole a token from a domain-privileged service account, and moved laterally to a domain controller. On the domain controller, they dumped credentials, enabled Windows Restricted Admin mode for pass-the-hash attacks, and extracted the NTDS.dit database, achieving full domain compromise.
A malicious actor exploited a Citrix NetScaler Gateway zero-day vulnerability on September 24, 2026, three days before public disclosure. The attacker attempted to establish persistence using a password-protected webshell and tried to escalate privileges by setting setuid and setgid bits on /bin/sh. The attack involved disguising a PHP webshell as a CSS file and manipulating web server aliases to evade detection. Although the targeted sensor was not compromised, the attack demonstrated sophisticated post-exploitation techniques for maintaining access and evading detection.
In September 2026, the Chinese threat actor UTA0565 exploited unpatched zero-day vulnerabilities in Google Chrome and Microsoft Windows through phishing campaigns targeting Asian government entities. The attacker used fake domains impersonating legitimate organizations to deliver an exploit chain leveraging CVE-2026-85046, CVE-2026-87491, and CVE-2026-85880. Successful exploitation resulted in deployment of CLEANGULP, a previously undocumented malware family with backdoor capabilities including command execution, file operations, and beacon object file execution. CLEANGULP communicated with command-and-control servers using encrypted HTTP traffic with custom encoding. Multiple Chinese APT groups shared access to this exploit kit, indicating coordinated cyber espionage activity during the vulnerability window. Patch status is not yet confirmed; organizations should monitor vendor advisories and apply patches once available.
The Head Mare APT group exploited two vulnerabilities in TrueConf video conferencing servers released since 2022 to deliver PhantomCore malware to conference participants. These vulnerabilities allowed attackers to execute arbitrary code, replace legitimate client installers with malicious versions, and deploy web shells. Infected installers deployed a backdoor granting attackers full control over infected systems. On Linux servers, additional backdoors used GitHub as a command and control channel. The vulnerabilities were patched in TrueConf server versions 5.3.9, 5.4.9, and 5.5.5 released in June 2026. Organizations with employees participating in TrueConf conferences may have been affected even without operating their own servers.
The Head Mare APT group exploited a chain of vulnerabilities in TrueConf video conferencing servers to deploy PhantomCore and PhantomGraph backdoors. Attackers connected to unpatched TrueConf servers via port 4307/TCP without authorization, using vulnerabilities KLCERT-26-057 and KLCERT-26-058 to execute arbitrary code with NT AUTHORITY\SYSTEM privileges. They replaced legitimate TrueConf client installers with infected versions containing PhantomCore, and deployed a web shell for persistent access. The PhantomGraph backdoor utilized Microsoft OneDrive as command-and-control infrastructure. Affected TrueConf versions included 5.3.X through 5.3.9, 5.4.X through 5.4.9, and 5.5.X through 5.5.5. Multiple Russian organizations across various industries were targeted, including instrument manufacturing, electronics, transportation, energy, IT, and software development. The vulnerabilities were patched in June 2026.
