Thirty-two Government services are offline and four are partially unavailable while work is carried out to address potential cybersecurity issues, a minister has said.
Organisations around the world have been scrambling to fix a critical security flaw in the programming language PHP used by the majority of websites.
Downing Street on Thursday said no large UK public-facing critical services have been affected, but some “limited” Government websites have gone dark while issues are resolved.
National Cyber Security Centre (NCSC) experts are working with OpenAI, whose technology was used to discover the vulnerabilities, and partners around the globe to address potential problems, a No 10 spokeswoman said.
Tech minister Baroness Lloyd of Effra told the House of Lords: “The information I have is that 32 Government services are unavailable and four are partially unavailable.”
She said that “has largely resulted from precautionary measures taken to protect systems while security updates and mitigations are applied”.
The Downing Street spokeswoman told reporters: “Work has already taken place across Government to identify and fix potential exposures to our systems, and our experts are continuing to work closely with both OpenAI and international partners on this issue.
“No large public-facing critical services are being affected by the exercise, but some limited services may temporarily be offline while security work is carried out.
“But this does not mean they were hacked, and work continues to resolve any issues.”
Officials said it was not “standard practice” to provide a list of Government services that were affected and that the picture was quickly evolving, with services being reviewed, updated and coming back online.
It came after cybersecurity chiefs warned UK organisations on Wednesday that a “critical security issue” had been discovered in PHP, which is used by almost 70% of websites according cybersecurity firm Cloudflare.
Lady Lloyd said the NCSC was briefed by OpenAI on the vulnerability “last week” and “the Government acted proactively ahead of public disclosure”.
Organisations have been urged by the NCSC to update to a new, fixed version of the PHP software – or consider taking their websites offline if they cannot be upgraded immediately.
The No 10 spokeswoman said: “Organisations of all sizes should follow NCSC guidance to protect their system.”
The NCSC said the scale of the issue was “unprecedented” and warned it would likely not be the last.
Chief technology officer Ollie Whitehouse said the centre had been carrying out a “co-ordinated disclosure process” warning organisations of the vulnerability after it was identified months ago.
“We’re in an era now of digital dependency, coupled with heightened cyber threat, coupled with kind of increasing capability, which means all organisations are going to likely have to revisit their risk assumptions and work out how they are able to invest in technology to be able to meet the contemporary era,” he told BBC Radio 4’s World At One programme.
Meanwhile, former GCHQ chief Sir David Omand warned that Russia and China will be exploiting the PHP bug.
Asked whether the two countries will have mobilised resources to exploit the issue, he told Times Radio: “Certainly both, and straightforward criminal gangs, just simply looking for acquisitive gain, or to launch ransomware attacks and so on.”
He added: “The targets that they will be most looking for are not the 30 million websites of small and medium-sized enterprises but nonetheless, I’ve no doubt they will be thinking of how would we exploit this vulnerability before everyone finally gets patched.”
Earlier, a minister said the security of next week’s Budget has not been compromised.
Scottish Secretary Douglas Alexander was asked whether the issues identified with PHP could result in major Budget leaks because the Office for Budget Responsibility (OBR) had to take down its website.
Mr Alexander told Times Radio on Thursday morning: “No, I’ve had no indication whatsoever that there’s any problem in terms of a breach of Budget security.
“Indeed John Healey, who I was with yesterday in Scotland, as I understand it initiated new security protocols reflecting his experience in the Ministry of Defence when he came to the Treasury as Chancellor in the summer.”
Last year, the OBR’s budget analysis was mistakenly published online ahead of then-chancellor Rachel Reeves’s statement to the Commons, allowing for early access to market sensitive information.
The PHP security issue identified could allow attackers to remotely control any web servers running PHP, which underpins popular platforms such as WordPress and Magento.
Many attempts at exploiting the vulnerability were spotted within hours of it being announced, according to Amazon and Cloudfare.
In an update published on the Amazon Web Services security blog, the company said its threat intelligence team found the flaw was “now being broadly exploited in the wild”.
Cloudfare chief executive Matthew Prince said on Thursday the firm spotted hundreds of thousands of hacking attempts within two hours of the announcement, with millions ongoing.
PHP developers had reportedly planned a security update on Thursday, but the release was brought forward after details of its work to address the vulnerabilities leaked online.
Alan Woodward, a visiting computer science professor at the Surrey Centre for Cyber Security (SCCS), said “the cat was let out of the bag rather earlier than it was supposed to have been”.
“There’s always a window between the flaw being publicly known about and it being patched so that the attackers can’t successfully get in,” Professor Woodward told BBC Radio 4’s Today programme.
“And what happened, unfortunately, the day before the patch was out, somebody let the cat out of the bag.
“There was an initial version of the patch that was released, and so it was very easy to compare the original with the patched version and see which bit of code you needed to go and exploit.”
The Wall Street Journal had reported that the flaw was discovered in August by Ryan Austin, a researcher at the cybersecurity company Calif, using an advanced AI model developed by OpenAI.
Professor Woodward explained the vulnerability had in fact already been identified by human researchers in 2024, but it was then believed exploiting this security flaw would be “too complicated”, and nothing was done.
“People have been scrambling away, saying, ‘Well, actually, yes, you can exploit it, and we now need to patch it’,” he said.
“And the patch came out yesterday afternoon – luckily, the PHP Foundation issued one, so that’s why everybody’s scrambling to make sure that that’s in place.”
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