The c-ares library, an asynchronous resolver library, is vulnerable to a denial of service (DoS) attack. This vulnerability arises when a target resolver sends a query, allowing an attacker to forge a malformed UDP packet with a length of 0. The target resolver mistakenly interprets this length as a signal for a graceful shutdown of the connection. The severity of this vulnerability is underscored by its CVSS score of 7.5, categorizing it as high severity.
Risk to organizations includes potential downtime and disruption of services, as the affected resolvers may become unresponsive when subjected to this malicious attack. Given the ease of execution (low attack complexity and no required privileges), the likelihood of exploitation is heightened, making it critical for organizations to act swiftly.
As of now, there are no known exploits available for this vulnerability, and it is not included in the Known Exploited Vulnerabilities (KEV) catalog. However, organizations should prioritize patching immediately, as the potential for exploitation exists.
The vulnerability was published on May 25, 2023, and has been patched in version 1.19.1 of the c-ares library. Organizations utilizing this library should ensure they are running the latest version to mitigate risks.
Vulnerability Details
The official CVE description states that c-ares is vulnerable to denial of service. The vulnerability type is classified as DoS, and it has a CVSS score of 7.5, indicating high severity. The affected product and vendor include c-ares and various Linux distributions such as Debian and Fedora. The vulnerability was disclosed on May 25, 2023, and is classified under CWE-400.
Technical Analysis
The root cause of this vulnerability lies in the handling of malformed UDP packets by the target resolver. When a query is sent, and a packet with a length of 0 is received, the resolver incorrectly interprets this as a graceful shutdown. This can lead to the resolver becoming unresponsive. The attack vector is through the network, and the attack complexity is low, requiring no privileges or user interaction. The availability impact is high, as it can render the resolver unusable.
Risk & Impact Analysis
Organizations should assess the deployment risk associated with this vulnerability, especially if they utilize Linux distributions that include the c-ares library. The blast radius potential is significant, as the denial of service could affect multiple services relying on the resolver. Given the CVSS score of 7.5, organizations should address this vulnerability in their priority patch cycle to prevent service interruptions.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The c-ares library versions prior to 1.19.1 are affected by this vulnerability. Additionally, Debian Linux versions 10.0 and 11.0, and Fedora versions 37 and 38 are also vulnerable.
Mitigation & Remediation
Organizations should update to c-ares version 1.19.1 or later to mitigate this vulnerability. If immediate patching is not possible, consider implementing network controls to filter malicious UDP packets. Regular monitoring for unusual behavior in resolver services is also recommended. For further guidance on security testing, organizations can refer to penetration testing practices.
Detection Guidance
Organizations should monitor logs for indicators of abnormal resolver activity, such as unexpected shutdowns or excessive resource consumption. Behavioral anomalies may indicate attempts to exploit this vulnerability. Additionally, network signatures associated with malformed UDP packets should be established to detect potential attacks.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability lies in the potential for widespread disruption across services utilizing c-ares. It highlights the need for rigorous security practices in the development and deployment of libraries. Security teams should prioritize understanding and mitigating similar vulnerabilities in their systems. Organizations can enhance their defenses by integrating security assessments into their software development lifecycle. For more insights, consider reading about penetration testing methodology and the role of vulnerability management programs in improving overall security posture. Additionally, exploring cloud penetration testing strategies can further bolster resilience against evolving threats.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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