CVE-2021-0283 is a high-severity buffer overflow vulnerability found in the TCP/IP stack of Juniper Networks' Junos OS. This vulnerability allows attackers to send specific sequences of packets to the device, leading to a Denial of Service (DoS) condition. An attacker can sustain this DoS condition by repeatedly sending these packet sequences, which causes the device to shut down abnormally. An indicator of compromise may be logged as: "eventd[13955]: SYSTEM_ABNORMAL_SHUTDOWN: System abnormally shut down." Notably, this issue is only triggered by traffic directed at the device; transit traffic does not activate the vulnerability.
The severity of this vulnerability is underscored by its CVSS score of 7.5, indicating a high level of risk. Organizations using affected versions of Junos OS are urged to address this vulnerability promptly as it poses a significant risk of operational disruption. The exploitation status is currently unknown, and no public exploit has been confirmed. However, given the nature of the vulnerability, organizations should take proactive measures to protect their environments.
Urgency for defenders is high, and organizations should prioritize patching immediately. This vulnerability affects multiple versions of Junos OS, including versions prior to 12.3R12-S19, 15.1R7-S10, and various other iterations up to 21.2R2. Ensuring systems are updated to secure versions is crucial to maintaining network integrity and availability.
The implications of CVE-2021-0283 extend beyond immediate operational concerns, as prolonged downtime could affect service delivery and customer trust. Organizations should remain vigilant and incorporate this vulnerability into their security posture assessments and incident response plans.
Vulnerability Details
A buffer overflow vulnerability in the TCP/IP stack of Juniper Networks Junos OS allows an attacker to send specific sequences of packets to the device thereby causing a Denial of Service (DoS). This vulnerability affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S19; 15.1 versions prior to 15.1R7-S10; 16.1 version 16.1R1 and later versions; 16.2 version 16.2R1 and later versions; 17.1 version 17.1R1 and later versions; 17.2 version 17.2R1 and later versions; 17.3 versions prior to 17.3R3-S12; 17.4 version 17.4R1 and later versions; 18.1 versions prior to 18.1R3-S13; 18.2 version 18.2R1 and later versions; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S9, 18.4R3-S9; 19.1 versions prior to 19.1R3-S6; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S7, 19.3R3-S3; 19.4 versions prior to 19.4R3-S5; 20.1 versions prior to 20.1R2-S2, 20.1R3-S1; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2; 21.2 versions prior to 21.2R1-S1, 21.2R2.
Technical Analysis
The root cause of this vulnerability lies in the improper handling of specific packet sequences by the TCP/IP stack. When these sequences are sent, they can lead to a buffer overflow, which in turn can cause the device to shut down unexpectedly. The attack vector for this vulnerability is network-based, requiring no privileges or user interaction for exploitation. The attack complexity is low, making it accessible to a wide range of attackers.
The confidentiality and integrity impacts are rated as none, while the availability impact is rated as high, indicating that this vulnerability can lead to complete service disruption. Organizations should consider implementing network segmentation and strict access controls to limit exposure to this threat.
Risk & Impact Analysis
Risk to organizations includes potential downtime and loss of service, which can result in significant operational impact and financial loss. The blast radius of this vulnerability is broad, affecting multiple versions of Junos OS across various deployments. Organizations should assess their exposure and prioritize remediation efforts based on the criticality of the affected systems.
The urgency for remediation is high due to the potential for exploitation. Organizations should prioritize patching immediately, particularly those operating on affected versions of Junos OS, to mitigate risks associated with this vulnerability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects the following versions of Junos OS: 12.3 versions prior to 12.3R12-S19; 15.1 versions prior to 15.1R7-S10; 16.1 version 16.1R1 and later; 16.2 version 16.2R1 and later; 17.1 version 17.1R1 and later; 17.2 version 17.2R1 and later; 17.3 versions prior to 17.3R3-S12; 17.4 version 17.4R1 and later; 18.1 versions prior to 18.1R3-S13; 18.2 version 18.2R1 and later; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S9, 18.4R3-S9; 19.1 versions prior to 19.1R3-S6; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S7, 19.3R3-S3; 19.4 versions prior to 19.4R3-S5; 20.1 versions prior to 20.1R2-S2, 20.1R3-S1; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2; 21.2 versions prior to 21.2R1-S1, 21.2R2.
Mitigation & Remediation
Organizations should prioritize patching to mitigate the risk associated with CVE-2021-0283. Available patches are provided for the affected versions. For those unable to apply patches immediately, consider implementing network segmentation and access controls to limit exposure to potential exploit attempts. Regularly monitor logs for indicators of compromise, such as abnormal shutdown messages.
For more comprehensive security evaluations, organizations may consider engaging in continuous security testing to ensure all potential vulnerabilities are identified and addressed.
Detection Guidance
Organizations should monitor network traffic for unusual patterns that may indicate an attack. Log entries that indicate abnormal shutdowns should also be scrutinized as potential indicators of exploitation. Additionally, behavioral anomalies in device performance may signal attempted exploitation of this vulnerability.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-0283 highlights the ongoing challenges organizations face in securing networked devices. As cyber threats evolve, vulnerabilities like this will continue to pose risks to operational integrity. Security teams should learn from this incident to strengthen their defenses, focusing on proactive measures such as penetration testing methodologies and robust incident response plans.
Additionally, organizations should stay informed about emerging vulnerabilities through resources such as vulnerability management programs and threat intelligence sharing platforms.
Finally, adopting a culture of security awareness among employees can significantly enhance an organization’s resilience against such vulnerabilities. For further insights, organizations may explore API security testing and other relevant security strategies.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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