CVE-2021-25214 is a medium-severity vulnerability identified in various versions of BIND. This vulnerability allows the named process to terminate unexpectedly when it receives a malformed IXFR (Incremental Zone Transfer). The affected versions include BIND 9.8.5 through 9.8.8, 9.9.3 through 9.11.29, 9.12.0 through 9.16.13, and certain versions of the BIND 9 Supported Preview Edition, as well as the 9.17 development branch. The risk to organizations includes potential denial of service due to the unexpected termination of the named process, especially during zone refresh operations.
With a CVSS score of 6.5, this vulnerability is classified as medium severity. The implications of this vulnerability highlight the necessity for organizations to maintain up-to-date systems and to implement timely patches to avoid service disruptions. The CVSS vector indicates that the attack can be executed over the network with low complexity and requires low privileges, making it accessible for potential attackers.
Organizations should prioritize patching immediately to mitigate the risk associated with this vulnerability. The exploitability of this vulnerability is classified as medium, which indicates that while public exploits are not confirmed, the potential for exploitation exists, especially given the nature of the vulnerability.
The vulnerability was published on April 29, 2021, and continues to be relevant as organizations work to secure their DNS infrastructure. Regular updates and monitoring for vulnerabilities such as CVE-2021-25214 are essential to maintaining a secure operational environment.
Vulnerability Details
This vulnerability allows the named process to terminate due to a failed assertion when handling a malformed IXFR. The affected systems include BIND versions specified above, which are critical for DNS operations. The CWE classification for this vulnerability is CWE-617, indicating improper restriction of operations within the bounds of a memory buffer.
Technical Analysis
The root cause of CVE-2021-25214 lies in the handling of IXFR requests. When a malformed IXFR is received, the named process fails to handle the situation gracefully, resulting in a crash. The attack vector is network-based, allowing an attacker to exploit this vulnerability remotely without requiring user interaction. The complexity of the attack is low, and the necessary privileges are also low, making it feasible for attackers to leverage this flaw.
The impacts of this vulnerability primarily affect availability, as the named process becomes unavailable following a crash. There is no impact on confidentiality or integrity. Organizations using these BIND versions should be aware of the potential for service interruptions and plan accordingly to mitigate this risk.
Risk & Impact Analysis
The real-world deployment of this vulnerability poses significant risks to organizations relying on BIND for DNS services. Given that DNS is a critical component of network infrastructure, the potential for denial of service attacks could lead to significant operational disruptions. Organizations should assess their exposure and the potential blast radius of an exploitation attempt.
The urgency for addressing this vulnerability is classified as medium. While it is not actively exploited in the wild, the nature of the vulnerability and its implications necessitate prompt action within the organization's patch management cycle. Regular reviews of vulnerabilities and their potential impacts should be part of a comprehensive security strategy.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions include BIND versions 9.8.5 through 9.8.8, 9.9.3 through 9.11.29, 9.12.0 through 9.16.13, and the 9.17 development branch up to version 9.17.11. Additionally, various supported preview editions are also impacted. Organizations should ensure that they are running versions that have addressed this vulnerability.
Mitigation & Remediation
To remediate this vulnerability, organizations should apply the latest patches provided by their respective vendors. For BIND, ensure you upgrade to a version that is not affected by this flaw. If patches are unavailable, implementing strict network controls and monitoring for unusual IXFR requests can be beneficial. Additionally, organizations should consider conducting regular security assessments to identify and address vulnerabilities proactively.
Detection Guidance
Monitoring logs for anomalies related to IXFR requests can help detect attempts to exploit this vulnerability. Organizations should also track the behavior of the named process for any unexpected terminations, which may indicate exploitation attempts.
AppSecure Threat Intelligence Insight
CVE-2021-25214 underscores the importance of maintaining secure DNS configurations and regular updates. The low exploitability of this vulnerability suggests that while it may not be a top concern, it is still significant. Security teams should prioritize continuous monitoring and have a robust patch management strategy in place to mitigate similar vulnerabilities in the future.
Organizations looking to strengthen their security posture should consider engaging in penetration testing to identify potential weaknesses before they can be exploited.
Known Exploitation Timeline
This section is not applicable as no KEV data exists for this vulnerability.
EPSS Risk Context
The EPSS score for this vulnerability is 0.0075, placing it in the lower percentile of risk. This indicates a low probability of exploitation in the wild, but organizations should not become complacent.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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