Wells Fargo on Tuesday afternoon said its online banking service was experiencing an “unusually high volume” of traffic that it believes is a result of a denial of service (DoS) attack against the bank.
“Today we’ve seen an unusually high volume of website traffic which we believe is a denial of service attack,” a Wells Fargo spokesperson told SecurityWeek.
The attack is likely linked to hacker group the Izz ad-Din al-Qassam Cyber Fighters, which warned that it would launch a series of cyber attacks against several large U.S. banks in protest of a video its considers offensive to Muslims, and listed Wells Fargo as a chosen target.
“The vast majority of customers are not impacted and customer information is safe,” the spokesperson said. “For customers who are having difficulty accessing the site, we encourage them to try logging on again as the disruption is usually intermittent.”
Last week the group claimed similar DDoS attacks against brands including BB&T, PNC, Chase, citibank, U.S. Bancorp, Suntrust, Fifth Third Bancorp, Wells Fargo, and others.
Earlier this month, Izz ad-Din al-Qassam Cyber Fighters promised new DDoS attacks against the finance sector, having previously targeted several American banks successfully. At the time their warning was delivered, Bank of America, PNC Bank, Wells Fargo, and Citibank were all having technical issues or were entirely inaccessible.
The same group had claimed responsibility for the earlier round of DDoS attacks that targeted U.S. banks the second half of last year. Those attacks sent upwards of 80 Gb/sec to 100 Gb/sec of traffic against the banking infrastructure, and combined multiple attack techniques, making it harder for defenders to successfully filter out the malicious traffic.