A vulnerability in the VPN System Logging functionality for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a memory leak that can deplete system memory over time, which can cause unexpected system behaviors or device crashes. The vulnerability is due to the system memory not being properly freed for a VPN System Logging event generated when a VPN session is created or deleted. An attacker could exploit this vulnerability by repeatedly creating or deleting a VPN tunnel connection, which could leak a small amount of system memory for each logging event. A successful exploit could allow the attacker to cause system memory depletion, which can lead to a systemwide denial of service (DoS) condition. The attacker does not have any control of whether VPN System Logging is configured or not on the device, but it is enabled by default.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Firepower_threat_defense | Cisco | 6.2.3.12 (including) | 6.2.3.12 (including) |
| Firepower_threat_defense | Cisco | 6.2.3.13 (including) | 6.2.3.13 (including) |
| Firepower_threat_defense | Cisco | 6.2.3.14 (including) | 6.2.3.14 (including) |
| Firepower_threat_defense | Cisco | 6.2.3.15 (including) | 6.2.3.15 (including) |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.