The threat actors manage to gain access to corporate network even the VPN is protected with MFA. And 2.75GB of data are stolen from Cisco.
IMO, using push
notification MFA can be insecure if it is mis-configured. Same for any 2FA or MFA, a mis-configured security controls is just a false sense of security.
Here is the initial vector from Cisco Talos.
Initial access to the Cisco VPN was achieved via the successful compromise of a Cisco employee’s personal Google account. The user had enabled password syncing via Google Chrome and had stored their Cisco credentials in their browser, enabling that information to synchronize to their Google account. After obtaining the user’s credentials, the attacker attempted to bypass multifactor authentication (MFA) using a variety of techniques, including voice phishing (aka "vishing") and MFA fatigue, the process of sending a high volume of push requests to the target’s mobile device until the user accepts, either accidentally or simply to attempt to silence the repeated push notifications they are receiving. Vishing is an increasingly common social engineering technique whereby attackers try to trick employees into divulging sensitive information over the phone. In this instance, an employee reported that they received multiple calls over several days in which the callers – who spoke in English with various international accents and dialects – purported to be associated with support organizations trusted by the user.
Once the attacker had obtained initial access, they enrolled a series of new devices for MFA and authenticated successfully to the Cisco VPN. The attacker then escalated to administrative privileges, allowing them to login to multiple systems, which alerted our Cisco Security Incident Response Team (CSIRT), who subsequently responded to the incident. The actor in question dropped a variety of tools, including remote access tools like LogMeIn and TeamViewer, offensive security tools such as Cobalt Strike, PowerSploit, Mimikatz, and Impacket, and added their own backdoor accounts and persistence mechanisms.
We all can learn more TTP (tactics, techniques, and procedures) from this Cisco breach at Cisco Talos.
Links: