In Docker before versions 9.03.15 and 20.10.3, there exists a vulnerability that allows an attacker to crash the dockerd daemon by pulling an intentionally malformed Docker image manifest. This vulnerability has been classified as medium severity with a CVSS score of 6.5, indicating that it poses a significant risk to the availability of the Docker service.
The attack vector is network-based, requiring user interaction to trigger the vulnerability. Although exploitation does not require any privileges, it can cause significant disruptions as the daemon is responsible for managing Docker containers. Versions 20.10.3 and 19.03.15 have been patched to prevent such crashes.
Risk to organizations includes potential downtime and service interruptions if the daemon crashes. Considering the widespread use of Docker in production environments, organizations should prioritize patching immediately.
As of now, there are no known public exploits or proofs of concept available for this vulnerability, but the possibility of future exploitation remains. Organizations should remain vigilant and monitor for any updates related to this issue.
Vulnerability Details
This vulnerability allows an attacker to crash the dockerd daemon by using a malformed Docker image manifest. The affected versions include Docker versions prior to 9.03.15 and 20.10.3. The CVSS score of 6.5 indicates a medium severity level, with an availability impact classified as high.
The vulnerability has been identified as CWE-400 (Uncontrolled Resource Consumption) and CWE-754 (Improper Check for Unusual or Exceptional Conditions). These classifications highlight the nature of the vulnerability and the potential impacts on service availability.
The vulnerability was published on February 2, 2021, and affects several products including Docker, Debian Linux, and NetApp's E-Series SANtricity OS Controller.
Technical Analysis
The root cause of this vulnerability lies in the Docker daemon's handling of image manifests. When a malformed manifest is pulled, the daemon fails to process it correctly, resulting in a crash. This indicates a flaw in how Docker validates input data from external sources.
The attack vector is network-based, and the complexity of the attack is low. Attackers may leverage this vulnerability without needing any privileges, but user interaction is required to initiate the crash by pulling the malformed image.
The confidentiality and integrity impacts are negligible, as the vulnerability primarily affects the availability of the daemon. Organizations should monitor their Docker environments for any suspicious activities that may indicate attempts to exploit this vulnerability.
Risk & Impact Analysis
The real-world risk associated with this vulnerability is significant, particularly for organizations relying on Docker for container orchestration. A successful exploitation could lead to downtime, affecting business operations and potentially causing data loss.
The blast radius is notable, as multiple services could be disrupted if the dockerd daemon crashes. Organizations using versions prior to the patched releases are especially vulnerable and should prioritize remediation efforts.
Considering the CVSS score and the lack of known exploits at this time, organizations should address this vulnerability in their priority patch cycle.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects Docker versions prior to 9.03.15 and 20.10.3. Additionally, Debian Linux version 10.0 and NetApp E-Series SANtricity OS Controller versions 11.0 to 11.60.3 are also impacted. Organizations should ensure they upgrade to the patched versions to mitigate the risk.
Mitigation & Remediation
Organizations should update their Docker installations to versions 20.10.3 or 19.03.15 to mitigate this vulnerability. If immediate patching is not possible, organizations can implement network controls to limit access to the Docker daemon until the patch can be applied.
Configuration hardening can also reduce the risk of exploitation. Regular monitoring of Docker environments for abnormal behavior is crucial to detect potential attacks early.
Organizations can validate remediation through penetration testing to ensure that similar vulnerabilities are not present.
Detection Guidance
To detect potential exploitation attempts, organizations should monitor logs for unusual access patterns to the Docker daemon. Behavioral anomalies, such as increased crashes or restart attempts of the daemon, should be investigated.
Network signatures indicating attempts to pull malformed image manifests should also be tracked. System changes related to Docker's operation should be logged and analyzed to identify any security incidents.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-21285 illustrates the need for robust input validation in software systems, particularly those exposed to network interactions. This vulnerability highlights a common trend where improper handling of unexpected input can lead to service disruptions.
Security teams should learn from this incident and adopt a proactive approach to vulnerability management. Regular updates and security assessments are essential to mitigate similar risks.
For further insights, organizations can refer to the penetration testing methodology and consider engaging in a vulnerability management program to better prepare for future vulnerabilities.
Lastly, adopting a continuous security approach can help organizations stay ahead of emerging threats, as outlined in our continuous security testing articles.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
.webp)