A serious OTP vulnerability has been discovered in the OTP feature of Airlift Express – an online grocery startup. Exploiting this vulnerability could allow an attacker to takeover target accounts.
Airlift Express OTP Vulnerability
Researchers from PrivacySavvy have highlighted a serious OTP vulnerability affecting Airlift Express. Airlift Express is an online grocery service from Airlift – a Pakistani decentralized urban mass transit startup.
As elaborated in their post, the researchers found the OTP feature of Airlift Express vulnerable to brute force attacks.
Basically, signing-in to Airlift Express is possible with an email address or a phone number. In case the user forgets the password, the app allows resetting the password via the ‘Forgot Password’ option. Clicking on this feature makes the app send an OTP to the users’ registered email address or phone number. Now the user has to enter the received OTP to the new prompt on the screen. The same window also bears the options to type in the new passwords.
This is where the vulnerability existed. An adversary knowing a target user’s phone number could hack the account by guessing the OTP and resetting the password.
The researchers, in their study, easily brute-forced the 4-digit OTP within 7 minutes. Once done, they gained complete access to the account.
Upon noticing the issue, PrivacySavvy team reached out to the vendors to report the bug. Consequently, Airlift fixed the vulnerability. As they confirmed in their post,
The company quickly responded to our report and fixed OTP vulnerability alongside other security issues.
However, this vulnerability simply shows the underlying weakness of this verification approach.
Instead, organizations and services relying on OTP for their users can shift to better security approaches such as multi-factor authentication.
Likewise, passwordless approaches (such as MIRACLE, DUO, and IANUM) also serve as safer authentication methods.
Whereas, applying CAPTCHAs is another strategy that services can employ to prevent brute-force attacks (just as Airlift did to fix the bug).