IHG has said that service at its call centres has been recovered and all systems restored following a cyberattack earlier this month.
A statement from the group said: "Following a period of disruption, by Wednesday 7 September IHG had re-activated its booking websites and mobile app together with most of its other booking channels and revenue-generating systems. Subsequently, service at our reservation and customer care call centres has been recovered and all our systems restored. During the disruption in our central systems, IHG-branded hotels continued to operate and were able to take reservations directly.
"We have continued to carry out additional steps as part of our recovery and assurance plans to review and further enhance our security measures. External specialists were engaged to investigate the incident, and no evidence of unauthorised access to systems storing guest data has been identified. We have also reported the criminal activity to law enforcement. We continue to work closely with our hotels and owners throughout this time."
Customers at the global hotel giant, which operates 6,000 properties worldwide under brands including Holiday Inn, Crowne Plaza, and Hotel Indigo, reported problems with booking on 5 September.
On 6 September IHG told investors it had been hacked, causing its reservations channels and other applications to be "significantly disrupted".
The hackers, who described themselves as a couple from Vietnam, told the BBC they gained access to IHG's Outlook emails, Microsoft Teams chats and server directories using the password Qwerty1234.
The hackers said they were able to access IHG's internal network by tricking an employee into downloading malicious software through an email attachment and bypassing a security prompt message sent to the worker's devices.
IHG was targeted by malware designed to access data from payments cards used at the front desk of several of its franchised hotels in the United States and Puerto Rico in 2016.
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