Belkin F9K1102 2 devices with firmware 2.10.17 use an improper algorithm for selecting the ID value in the header of a DNS query, which makes it easier for remote attackers to spoof responses by predicting this value.
Belkin F9K1102 routers with firmware 2.10.17 are vulnerable to DNS spoofing, allowing attackers to redirect network traffic to malicious servers. This vulnerability stems from a flawed implementation of DNS query ID selection, making it trivial for attackers to predict and forge DNS responses. Successful exploitation can lead to man-in-the-middle attacks, data theft, and network compromise.
Step 1: Target Identification: The attacker identifies the target Belkin F9K1102 router and determines its IP address.
Step 2: DNS Request Observation: The attacker monitors the network traffic to observe DNS requests originating from the target router.
Step 3: ID Prediction: Based on observed DNS requests, the attacker attempts to predict the next DNS query ID used by the router. This is possible due to the weak ID generation algorithm.
Step 4: Malicious Response Crafting: The attacker crafts a malicious DNS response with the predicted ID, spoofing the DNS record for a target domain (e.g., a bank's website).
Step 5: Response Injection: The attacker sends the crafted DNS response to the target router, aiming to arrive before the legitimate DNS response.
Step 6: Cache Poisoning: If the attacker's response arrives first, the router caches the malicious DNS record.
Step 7: Traffic Redirection: Subsequent requests from the router for the target domain are directed to the attacker's server, enabling a man-in-the-middle attack.
The vulnerability lies in the use of a predictable or weak algorithm for generating the DNS query ID in the header of DNS requests. The router's firmware likely uses a simple counter or a poorly seeded random number generator to assign these IDs. This predictability allows an attacker to craft malicious DNS responses with the correct ID, which the router will accept as legitimate. The attacker can then poison the router's DNS cache, redirecting traffic intended for legitimate websites to attacker-controlled servers. The root cause is a lack of entropy in the ID generation process, making it easy to guess the ID and forge responses. This is not a buffer overflow or race condition vulnerability, but rather a logic flaw in the DNS implementation.