Chinese hackers build PHP2SHELL exploit, use it to root 25 servers, breach US government-affiliated firewalls

(Image credit: Shutterstock) Researchers report the first confirmed PHP2Shell compromises, targeting organizations linked to the US governmentAttackers chained PHP2Shell with a Linux privilege-escalation flaw to gain root access and persistenceBreaches progressed from initial compromise to Active Directory attacks within minutes, underscoring patching urgencyWe now have confirmation of the first successful exploits of the infamous PHP2Shell vulnerability discovered earlier this month.The news comes courtesy of cybersecurity outfit Dream, who claim to have seen attackers breach organizations affiliated with the US government.PHP2Shell is a name given to two critical-severity vulnerabilities found in PHP. When they were first disclosed, most of the cybersecurity community went full panic mode, given that PHP powers roughly 70% of all websites and web apps on the internet, and there was no patch at the time. The flaws allegedly enabled complete website takeover, and some government and education organizations in Europe even preemptively shut down their websites, in anticipation of mass exploitation attempts.But after the dust settled, a strange thing happened - there were no successful attacks. Researchers were seeing attempts and probes, but no successful breaches. Amazon said it observed first attacks four days before the patch, and Cloudflare later tracked “thousands” of attempts in the 10 hours before the patch was announced. This grew to tens of thousands within an hour of disclosure, and hundreds of thousands within two hours. Now, it’s gone into the millions.Some said exploiting the bugs was easier said than done, and that threat actors were hitting different roadblocks, including Address Space Layout Randomization, a security feature that randomly changes where a program’s code and data are stored in memory every time it runs. Still, they warned that all of that might be temporary, and that a successful hit was a question of “when”, not “if”.Targeting firewallsNow it seems the claims were on point, as Dream says Chinese threat actors successfully chained PHP2Shell with a Linux kernel privilege-escalation flaw against Palo Alto Networks firewalls, breaching 25 servers, some allegedly belonging to US government-affiliated organizations.The attacks started on October 23 2026, probing firms in the US, Japan, Taiwan, and South Korea, and soon focused on Palo Alto Networks’ PAN-OS-powered devices, running an older, vulnerable version of the OS.Sign up to the TechRadar Pro newsletter to get all the top news, opinion, features and guidance your business needs to succeed!According to Dream, the crooks chained PHP2Shell with Fragnesia, a local privilege escalation flaw that allows unprivileged users to obtain root access. It was disclosed in mid-May this year and is tracked as CVE-2026-46300.After breaking into the devices, the attackers ran some 40 custom post-exploitation scripts, Dream added.“Within hours of compromising a US government-affiliated firewall, they had tunneled into the internal network, compromised a third server using the same PHP2Shell exploit, and launched a full Active Directory attack campaign - all through a chain that started with a single unauthenticated HTTPS request to a management interface that should never have been exposed to the internet,” the company’s report reads.Not automatedTo make matters worse, the researchers believe the attackers still have unabated access.“The total chain - from unauthenticated HTTPS connection to persistent root webshell - completes in under 15 minutes,” Dream said. The researchers could not say what the endgame was here because that information was not found in the artifacts they retrieved. Besides the obvious, which seems to be persistent access and credential theft, the threat actors could do anything from dropping backdoors to exfiltrating sensitive information.In the context of “Black October”, and the fact we’re seeing a significant increase in automated attacks, it is also worth mentioning that this incident was likely not AI-powered.Dream did find evidence of AI usage but believes it was not fully automated. Claude Code was installed, as was an offensive security platform called AIscan, which was configured with Chinese AI models DeepSeek and Kimi. Furthermore, they found API keys for FOFA, a Chinese counterpart to the Shodan search engine.With the help of FOFA, the attackers allegedly identified around 19,000 internet-connected Palo Alto Networks firewalls, which they used as a starting point for their attacks.Via The Register Follow TechRadar on Google News and add us as a preferred source to get our expert news, reviews, and opinion in your feeds. Sead is a seasoned freelance journalist based in Sarajevo, Bosnia and Herzegovina. He writes about IT (cloud, IoT, 5G, VPN) and cybersecurity (ransomware, data breaches, laws and regulations). In his career, spanning more than a decade, he’s written for numerous media outlets, including Al Jazeera Balkans. He’s also held several modules on content writing for Represent Communications.