CVE-2010-2244 in Avahi
Summary
by MITRE
The AvahiDnsPacket function in avahi-core/socket.c in avahi-daemon in Avahi 0.6.16 and 0.6.25 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a DNS packet with an invalid checksum followed by a DNS packet with a valid checksum, a different vulnerability than CVE-2008-5081.
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Analysis
by VulDB Data Team • 07/31/2024
The vulnerability identified as CVE-2010-2244 affects the Avahi daemon implementation specifically within the avahi-core/socket.c file where the AvahiDnsPacket function processes incoming DNS packets. This issue represents a denial of service condition that can be exploited remotely by crafting malicious DNS packet sequences that trigger an assertion failure leading to daemon termination. The vulnerability occurs when the daemon receives a DNS packet with an invalid checksum followed by a subsequent packet with a valid checksum, creating a specific sequence that causes the system to fail an internal assertion and subsequently exit the daemon process.
The technical flaw stems from inadequate input validation within the DNS packet processing logic of the Avahi daemon. When the AvahiDnsPacket function handles the first packet with an invalid checksum, it likely stores or processes this data in a manner that creates an inconsistent internal state. The subsequent packet with a valid checksum then triggers a condition where the daemon's internal assertion mechanisms detect an unexpected state or data inconsistency, causing the assertion to fail and the daemon to terminate abruptly. This type of vulnerability falls under the category of improper input validation and can be classified as CWE-248, which addresses an exception is thrown for an unexpected input or condition.
The operational impact of this vulnerability extends beyond simple service disruption as it affects network infrastructure that relies on Avahi's mDNS/DNS-SD services for service discovery and local network communication. When exploited, the vulnerability can cause cascading effects in environments where Avahi daemon is critical for network operations, potentially leading to service unavailability for local network services, device discovery failures, and disruption of automatic network configuration processes. The vulnerability is particularly concerning in embedded systems and network appliances where Avahi is commonly deployed for zero-configuration networking services, as these systems may not have redundant service mechanisms to recover automatically from such failures.
Security professionals should note that this vulnerability differs from CVE-2008-5081, indicating that it represents a distinct attack vector within the same software family. The attack requires specific packet sequencing that makes it somewhat more complex to exploit compared to simpler denial of service conditions, but still represents a valid threat to network availability. Organizations should implement immediate mitigations including updating to patched versions of Avahi, implementing network monitoring for unusual DNS packet patterns, and potentially deploying firewall rules to limit DNS packet processing from untrusted sources. The vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how improper error handling in network services can create exploitable conditions for attackers seeking to disrupt availability of critical infrastructure services.