CVE-2008-3630 in Bonjour
Summary
by MITRE
mDNSResponder in Apple Bonjour for Windows before 1.0.5, when an application uses the Bonjour API for unicast DNS, does not choose random values for transaction IDs or source ports in DNS requests, which makes it easier for remote attackers to spoof DNS responses, a different vulnerability than CVE-2008-1447.
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Analysis
by VulDB Data Team • 08/17/2019
The vulnerability described in CVE-2008-3630 affects Apple Bonjour for Windows mDNSResponder implementation prior to version 1.0.5, specifically when applications utilize the Bonjour API for unicast DNS resolution. This flaw represents a significant security weakness in the network discovery and service discovery mechanisms that Bonjour provides for Windows environments. The issue stems from the implementation's failure to properly randomize critical components of DNS query packets, creating predictable patterns that adversaries can exploit to manipulate network communications.
The technical flaw manifests in the mDNSResponder's DNS request construction process where transaction IDs and source ports are not being randomized as required by standard DNS protocol implementations. According to CWE-330, this represents a weakness in randomness where insufficient entropy is used in cryptographic or security-critical operations. The vulnerability specifically affects the unicast DNS functionality within the Bonjour API, which is commonly used by applications to discover network services and resolve hostnames. When transaction IDs and source ports remain predictable, attackers can craft spoofed DNS responses that appear legitimate to the client, as the responses will match the expected transaction identifiers and source port numbers.
The operational impact of this vulnerability extends beyond simple DNS spoofing attacks, as it enables man-in-the-middle scenarios where remote attackers can redirect network traffic or inject malicious content into applications relying on Bonjour for service discovery. This weakness creates a pathway for attackers to manipulate network communications in ways that can compromise application integrity and potentially lead to broader system compromise. The vulnerability operates at the network protocol level and affects any application that depends on Bonjour's unicast DNS resolution capabilities, making it particularly dangerous in enterprise environments where service discovery is widely used. The attack vector requires only network access to observe DNS transactions and predict the patterns, making it relatively easy to exploit compared to other DNS-related vulnerabilities.
Security practitioners should implement immediate mitigations including updating to Apple Bonjour for Windows version 1.0.5 or later, which addresses the randomization issue in transaction IDs and source ports. Network segmentation and monitoring solutions can help detect anomalous DNS traffic patterns that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol: DNS, where adversaries leverage DNS protocols to establish persistence and exfiltrate data. Organizations should also consider implementing DNS sinkhole configurations and network access controls to limit the potential impact of successful spoofing attempts. Additionally, application developers should review their Bonjour API usage patterns to ensure they are not inadvertently exposing systems to this vulnerability through improper DNS resolution handling. The fix implemented by Apple addresses the core randomness issue and aligns with established security best practices for DNS protocol implementations as outlined in RFC 1035 and subsequent DNS security enhancements.