Customers reported being unable to access their accounts, and several Bank Sepah branches were forced to close temporarily as a result of the attack.
Fars News, linked to the IRGC, confirmed the attack but said that a quick resolution was expected.
A statement from Predatory Sparrow read: “We conducted cyberattacks which destroyed the data of the IRGC’s Bank Sepah.
"We thank the brave Iranians who helped make this operation possible.”
The group has been a thorn in the regime’s side for some years now, rising to prominence after causing a fire at a major Iranian steelworks in 2022.
In that attack, hackers were able to activate one of the site’s machines and cause it to leak molten metal, but claimed they had timed the operation to avoid casualties among innocent factory workers.
Itay Cohen, head of cybersecurity firm Check Point Software, even suggested at the time that the collective may be state-sponsored given its significant capabilities.
He told BBC News: “They claim themselves to be a group of hacktivists, but given their sophistication, and their high impact, we believe that the group is either operated, or sponsored by, a nation state."
