The May 5, 2023 disruption to DBS' digital banking services for more than six hours was caused by human error, preliminary investigations revealed.
Senior Minister Tharman Shanmugaratnam said on Jul. 5 in a written answer to a parliamentary question that the bank found "human error in coding the programme that was used for system maintenance", which affected access to its online and automated teller machine (ATM) services for over six hours.
"The error led to a significant reduction in system capacity, which in turn affected the system’s ability to process internet and mobile banking, electronic payment and ATM transactions," Tharman added.
Tharman was responding to Member of Parliament Tan Wu Meng, who had also asked what was being done to strengthen the reliability and resilience of retail banks' digital services in Singapore.
DBS initially said on May 5 that the disruption was a "systems issue" unrelated to an earlier day-long disruption in March.
According to the bank, the March disruption was caused by "inherent software bugs", Tharman added.
The May 5 error led to a significant reduction in system capacity, which in turn affected the system’s ability to process internet and mobile banking, electronic payment, and ATM transactions, Tharman said.
Second disruption in two months “unacceptable”: MAS
Tharman’s response also noted that the Monetary Authority of Singapore (MAS) has stated publicly that it regarded “this second disruption within a period of two months as unacceptable”, and that “DBS had fallen short of MAS’ expectation for banks to deliver reliable services to their customers”.
According to Tharman, who will step down as MAS chairman on Jul. 7 this year, MAS requires all retail banks in Singapore to ensure that their mission critical systems supporting digital banking are resilient.
This includes having the ability to recover quickly from any system disruptions.
As a result, MAS imposed an additional capital requirement on DBS on May 6, one day after the disruption.
Tharman noted that MAS may vary the size of the additional capital requirement and take other regulatory actions depending on the outcome of ongoing reviews.
DBS convened a special committee
Tharman also said that since the March 2023 disruption, DBS had convened a special committee to oversee the root cause investigation and a comprehensive review of the bank’s IT resilience.
However, after the disruption in May, MAS required DBS’ committee to extend its review to cover the May incident and to use qualified independent third parties for the review.
DBS is expected to provide more details on the disruptions to the public when the review is completed.