A vulnerability has been identified in SIMATIC S7-200 SMART CPU CR40 (6ES7288-1CR40-0AA0) (All versions), SIMATIC S7-200 SMART CPU CR60 (6ES7288-1CR60-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR20 (6ES7288-1SR20-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR20 (6ES7288-1SR20-0AA1) (All versions), SIMATIC S7-200 SMART CPU SR30 (6ES7288-1SR30-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR30 (6ES7288-1SR30-0AA1) (All versions), SIMATIC S7-200 SMART CPU SR40 (6ES7288-1SR40-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR40 (6ES7288-1SR40-0AA1) (All versions), SIMATIC S7-200 SMART CPU SR60 (6ES7288-1SR60-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR60 (6ES7288-1SR60-0AA1) (All versions), SIMATIC S7-200 SMART CPU ST20 (6ES7288-1ST20-0AA0) (All versions), SIMATIC S7-200 SMART CPU ST20 (6ES7288-1ST20-0AA1) (All versions), SIMATIC S7-200 SMART CPU ST30 (6ES7288-1ST30-0AA0) (All versions), SIMATIC S7-200 SMART CPU ST30 (6ES7288-1ST30-0AA1) (All versions), SIMATIC S7-200 SMART CPU ST40 (6ES7288-1ST40-0AA0) (All versions), SIMATIC S7-200 SMART CPU ST40 (6ES7288-1ST40-0AA1) (All versions), SIMATIC S7-200 SMART CPU ST60 (6ES7288-1ST60-0AA0) (All versions), SIMATIC S7-200 SMART CPU ST60 (6ES7288-1ST60-0AA1) (All versions). Affected devices do not properly handle TCP packets with an incorrect structure. This could allow an unauthenticated remote attacker to cause a denial of service condition. To restore normal operations, the network cable of the device needs to be unplugged and re-plugged.
The product does not properly control the allocation and maintenance of a limited resource.
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.