A cyber attack may be behind an outage that delayed thousands from registering to vote ahead of the EU referendum, according to a Parliamentary committee.
The public administration and constitutional affairs committee (PACAC) said it could not rule out a DDoS-style attack perpetrated by a foreign power, like Russia or China, in its a nalysis of the crash affecting the UK government's Register to Vote site last June.
As a result of the outage, the registration deadline was extended from 7 June to 11.59pm on 9 June.
Unprecedented traffic was blamed for the site falling over, with the government seeing a spike in users rushing to sign up in the last weeks before the Brexit referendum.
But while PACAC's own investigation into the affair recognised the "exceptional surge in demand" among citizens to register their rights to vote, it also said the crash "had indications" of being a DDoS attack, pointing to the timing of the traffic and the sheer volume of applications - with 515,000 being made on the day of the failure.
"Although the Committee has no direct evidence, it considers that it is important to be aware of the potential for foreign interference in elections or referendums," it said, adding that foreign states' motives for such an attack could be to influence how people vote.
"The US and UK understanding of 'cyber' is predominantly technical and computer-network based," PACAC's report read. "Russia and China use a cognitive approach based on understanding of mass psychology and of how to exploit individuals. The implications of this different understanding of cyber-attack, as purely technical or as reaching beyond the digital to influence public opinion, for the interference in elections and referendums are clear."
The Cabinet Office refuted the suggestion that the website was hacked, with a spokesperson saying: "There is no evidence to suggest malign intervention."
They added: "We have been very clear about the cause of the website outage in June 2016. It was due to a spike in users just before the registration deadline. We conducted a full review into the outage and have applied the lessons learned. We will ensure these are applied for all future polls and online services."
PACAC's report does not cite any sources for the hacking allegations. It comes after the US openly accused Russia of interfering in its presidential election, with security agencies blaming Russian hacking for President Donald Trump's surprise victory.
Among other allegations, the US blamed Russia for the release of thousands of Democratic National Committee emails, which WikiLeaks published. Former President Barack Obama ordered an investigation into Russia's alleged involvement.
Since then, Germany and France have sounded alerts about cyber attacks during elections.
At the time of the Register to Vote crash, sources close to government told IT Pro the outage occurred because the website's infrastructure was unable to cope with the huge traffic demands.
It was hosted on an in-house private cloud that could not scale to accommodate the volume of visits. The Government Digital Service, which developed the application along with contractors, did not build in any failover capacity, so when the site fell over, users were not redirected to another instance of the site.
Cyber security firm Veracode's EMEA solution architects manager, Paul Farrington, said the government must ensure it is able to protect future elections from hackers.
"Hacking an entire election is near impossible, but should digital elections be successfully implemented, any cyber criminal hoping to create suspicion and disrupt the result of an election could achieve this simply by affecting just a small number of votes," he said.
"While today we can't be sure as to whether a cyber attack has indeed denied citizens their democratic right, it is yet another reminder of the importance of robust cyber defences to plug vulnerabilities and defend against such potential dangers."
