iAuthFlow V2 is a new phishing toolkit demonstrating the rapidly improving sophistication of phishing techniques.
iAuthFlow V2 is a malware toolkit first seen on a Russian-language cybercrime forum. It is an advanced form of phishing that offers persistent access to the victim’s account, surviving a password reset.
The base toolkit is offered for sale at $10,000, with additional modules available separately. Using available information from the seller’s forum posts and demonstrations (but without acquiring or running the malware), Abnormal researchers have postulated an analysis of its operation, based on the ‘passkey’ module and employed against a Gmail account.
The target is phished in the normal manner, landing on an attacker-controlled web page that is displayed in the target’s browser. The attack requires the phish to be successful, and for the target to be fooled into entering credentials. However, unseen by the target, the attacker has a separate but connected second browser environment on the attacker’s own server.
In the normal course of events, a compromise is detected either rapidly or eventually. Standard procedure for the victim is a password reset, which breaks the attacker’s access. But not if iAuthFlow V2 is the compromise method. As the target interacts with the primary phishing page, the credentials and authentication responses are relayed to the remote browser, which is what actually responds to the target.
The malware immediately applies a device fingerprint to the target’s browser. Each entry from the target is logged. The malware silently adds a ready-made passkey, and all is relayed to the second browser environment. Google, from the second browser but via the initial phishing page, asks the target to authenticate. If the initial phish is successful, the target will do so, but without knowing that this now includes authenticating the attacker-controlled passkey.
When the victim discovers the compromise, a password reset and session revocation will normally cut off the attacker’s access – and is the standard response to a phishing compromise.
“Changing the password and revoking active sessions are standard responses to a compromised mailbox. When an attacker’s access is limited to captured session cookies, those actions normally end that access,” explains Abnormal in its attack analysis. “Google also states that changing a password revokes app passwords and OAuth tokens with Gmail scopes, although some authorized devices and third-party connections may remain signed in.”
But this process does nothing to the new passkey which is a credential registered to the account rather than a token derived from the password. It is now controlled by the attacker and can be used for future access. To regain access, the attacker need only ‘try another way’ at login and use the passkey without needing to know the password.
It should be stressed that this analysis from Abnormal is based on the iAuthFlow V2 seller’s online posts rather than actual use of the malware. Gemini describes the malware as “a commercial phishing-as-a-service (PhaaS) toolkit / framework marketed and sold to cybercriminals on underground hacking forums (such as the Exploit forum).” It makes no mention of passkeys. Copilot’s response is even more confused. So, it should be understood that very little is known about iAuthFlow V2.
This lack of public knowledge of the toolkit is understandable given its cost and (if Abnormal has it right) stealthy operation. What its existence and Abnormal’s analysis does demonstrate, however, is the increasing sophistication of social engineering technology.
Abnormal’s analysis includes IOCs and remediation advice. Fundamentally it suggests that a password reset is no longer sufficient to rectify a phisher’s compromise.
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