SINGAPORE - A problem with DBS Bank's access control servers disrupted its online banking services, including PayNow, for the second day on Wednesday (Nov 24).
Reacting to the bank's worst outage in more than a decade, the Monetary Authority of Singapore (MAS) said it will consider taking "supervisory action".
"This is a serious disruption and MAS expects DBS to conduct a thorough investigation to identify the root causes and implement the necessary remedial measures," said MAS assistant managing director of banking and insurance Marcus Lim.
"MAS will consider appropriate supervisory actions following the investigation," he added in a statement on Wednesday evening.
"MAS expects all financial institutions to have systems and processes to ensure the consistent availability of financial services to their customers," he said.
Under MAS regulations, financial institutions must ensure that the total unscheduled downtime for critical systems affecting services for customers does not exceed four hours within any 12-month period.
Banks must also inform MAS of any incidents affecting critical systems within an hour.
In a Facebook video post on Wednesday, DBS country manager for Singapore Shee Tse Koon apologised to affected customers for causing them inconvenience and blamed faulty access control servers for the outage.
He did not elaborate on details of the server fault.
Access control servers are part of a bank's security system. They handle both log-in and payment verification using means such as biometrics, authentication tokens and one-time passwords.
"Please rest assured that my colleagues and I are doing all that we can to remedy the situation," Mr Shee said.
The disruption, which was first reported at around 10am on Tuesday, is the worst DBS has seen since 2010, when a major systems failure took down all consumer and business banking services at DBS. Customers were unable to withdraw cash from ATMs or make point-of-sale payments for about seven hours.
Mr Shee on Wednesday assured customers that cash deposits belonging to DBS and POSB customers are safe, and transactions can still be made in person at bank branches or through phone banking.
The bank said services were fully restored at around 2am on Wednesday but the same problem later recurred, with users complaining they were still unable to log in to the app and website at around 9am.
"I know that many of you have been facing difficulties accessing our digital banking services. I realise that this is a cause for concern and frustration, and I'm very sorry for the inconvenience and the anxiety it has caused," Mr Shee said.
He added: "While the situation is less severe than yesterday, we know that many of you are still unable to get access. We acknowledge the gravity of the situation and as we work to resolve matters, we seek your patience and understanding."
As at 5pm on Wednesday, users said some functions such as ATM withdrawals, card payments and DBS PayLah! were working, but the DBS website and mobile app were still inaccessible.
At 10.35pm, DBS said its digital banking services were "returning to normal", adding that it was monitoring the situation closely to ensure all services run smoothly.
Home-based baker Adeline Tan, 25, who sells her wares on Instagram, was among those affected by the disruption.
"Some of my customers were not able to make payment via PayNow today, but they are my regular customers, so I'm okay with them not paying yet as I trust that they'll pay once their DBS apps are working," she said.
"I usually pay my egg supplier via PayNow too and I haven't been able to since yesterday, but he has been very understanding."
Administrative assistant Clarice Pereira, 55, had to cancel a booking she had made for a nurse to look after her brother, a stroke patient, this weekend.
The service required payment to confirm the booking, and DBS is the only bank she uses for Internet banking, she said.
Ms Pereira managed to find a different service that agreed to take payment later, but she said the incident had prompted her to look into services at other banks.
"This has taught me not to rely on one bank for Internet banking," she added.
While DBS customers outside Singapore also could not access their Singapore-based accounts, those with accounts that were opened under the bank's overseas branches were not affected.
DBS spokesmen in Hong Kong, India and Indonesia told The Straits Times that their services were not facing any disruptions.
The bank also debunked rumours that the disruption in Singapore was linked to the sale of treasury bonds in Myanmar.
DBS said in a tweet on Wednesday: "There have been rumours that DBS' digibanking service disruption is linked to the sale of treasury bonds by Myanmar's National Unity Government. There is no truth to this. DBS has not sold any such bonds."
A number of news outlets in Myanmar had reported that the disruption was caused by a high volume of transactions after Myanmar nationals used DBS and POSB online services to buy zero-interest bonds issued by the National Unity Government (NUG).
Reuters news agency on Wednesday reported that the NUG had raised US$6.3 million (S$8.6 million) on the opening day of its inaugural bond sale on Monday to mainly Myanmar nationals overseas.
The NUG's target is to raise US$1 billion for a "revolution" to oust the military government that seized power in a coup in February.
Past service outages at Singapore banks
July 2021
UOB customers were unable to access Internet and mobile banking services for about two hours. The bank apologised for the incident but did not provide details on what caused it.
November 2020
Some DBS customers faced difficulties in accessing the business banking portal DBS Ideal for about a day. DBS said a small number of its corporate customers were facing "intermittent delays" but did not elaborate on the cause of the issue.
June 2019
UOB's ATM, card payment, Internet banking and mobile application services were disrupted for about two hours. The bank apologised for the incident but did not provide details on what caused it.
September 2018
OCBC's ATM network, online banking channels, Nets and card services were disrupted for about three hours. OCBC said a software failure caused the bank's systems to stop accepting new data, and subsequent human oversight resulted in the glitch not being detected for rectification earlier.
July 2018
UOB apologised for a five-minute disruption to its ATM services.
February 2018
Human error during maintenance works caused an islandwide service disruption to the Nets cashless payment system owned by DBS, OCBC and UOB. The disruption lasted nearly two hours.
November 2012
Several DBS and POSB ATMs were out of service for an unspecified amount of time. DBS did not reveal the total number of affected ATMs or the cause of the issue.
September 2012
UOB's ATMs and Nets services were disrupted for about an hour due to a technical fault.
September 2011
A system-wide technical glitch affected OCBC's ATMs, card payments and Internet banking platforms for over four hours. A faulty connectivity device was blamed for the glitch, which "prevented the core banking system from connecting properly to the various front-end banking systems", OCBC said then.
The Monetary Authority of Singapore (MAS) reprimanded the bank, and ordered it to conduct thorough reviews of its systems.
July 2010
An incorrect maintenance procedure by IBM engineers caused a major systems failure that took down all consumer and business banking services at DBS. Customers were unable to withdraw cash from ATMs or make point-of-sale payments for about seven hours.
The bank was censured by MAS and was required to set aside an extra $230 million in regulatory capital for operational risk.
