CVE-2010-2812 in ZNC
Summary
by MITRE
Client.cpp in ZNC 0.092 allows remote attackers to cause a denial of service (exception and daemon crash) via a PING command that lacks an argument.
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Analysis
by VulDB Data Team • 09/23/2021
The vulnerability identified as CVE-2010-2812 affects the ZNC IRC bouncer software version 0.092, specifically within the Client.cpp component. This represents a classic input validation flaw that demonstrates how improper handling of user-supplied data can lead to system instability and service disruption. The ZNC software serves as a proxy between IRC clients and IRC servers, allowing users to maintain persistent connections even when their clients disconnect, making it a critical component in IRC networking infrastructure.
The technical flaw manifests when the ZNC daemon processes a PING command that is missing its required argument. In IRC protocol, PING commands typically require a parameter that serves as a timestamp or identifier for the ping operation. When this argument is omitted, the Client.cpp module fails to properly validate the incoming command structure, leading to an unhandled exception that ultimately causes the entire daemon process to crash. This vulnerability operates at the application layer and requires only a minimal network connection to exploit, making it particularly dangerous in environments where ZNC serves as a critical networking component.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited by remote attackers to perform denial of service attacks against ZNC instances. The daemon crash results in complete loss of IRC connectivity for all users connected through that particular ZNC instance, effectively severing network communications and potentially disrupting collaborative work environments or community channels that depend on continuous IRC access. This type of vulnerability directly impacts the availability aspect of the CIA triad and can be leveraged in broader attack campaigns targeting IRC infrastructure.
From a security perspective, this vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and demonstrates how insufficient input sanitization can lead to application instability. The ATT&CK framework categorizes this as a denial of service technique, specifically within the execution phase where adversaries manipulate application behavior to cause system failures. The vulnerability's exploitation requires minimal technical skill and network access, making it a preferred target for attackers seeking to disrupt services without requiring advanced penetration techniques.
The recommended mitigation strategy involves implementing proper input validation within the Client.cpp module to ensure that all PING commands contain required arguments before processing. This requires adding a validation check that verifies the presence and proper formatting of command parameters. Additionally, the ZNC development team should implement robust exception handling mechanisms that prevent unhandled exceptions from causing daemon crashes. The most effective long-term solution involves upgrading to a patched version of ZNC that addresses this specific input validation issue, while network administrators should consider implementing monitoring systems to detect unusual daemon crash patterns that may indicate exploitation attempts.