CVE-2019-0053 : Security Advisory and Response
Learn about CVE-2019-0053 involving stack-based buffer overflows in Junos OS telnet client, impacting Juniper Networks systems. Find mitigation steps and updated software releases.
CVE-2019-0053, assigned by Juniper, involves insufficient validation of environment variables in the telnet client provided with Junos OS, potentially leading to stack-based buffer overflows and bypassing veriexec restrictions.
Understanding CVE-2019-0053
What is CVE-2019-0053?
Insufficient validation of environment variables in the telnet client provided with Junos OS can result in stack-based buffer overflows, allowing attackers to bypass veriexec restrictions.
The Impact of CVE-2019-0053
Exploiting this vulnerability can lead to unauthorized access and potential compromise of affected systems running Junos OS.
Technical Details of CVE-2019-0053
Vulnerability Description
The vulnerability arises from inadequate validation of environment variables in the telnet client of Junos OS, enabling stack-based buffer overflows.
Affected Systems and Versions
- Juniper Networks Junos OS versions 12.3 to 18.4 are affected by this vulnerability.
Exploitation Mechanism
Attackers can exploit this vulnerability through the telnet client accessible via CLI or shell in Junos OS, circumventing veriexec restrictions.
Mitigation and Prevention
Immediate Steps to Take
- Limit access to Junos CLI and shell to trusted administrators only.
- Block outbound telnet connections.
- Deny access to the telnet command and shell per user or user class.
Long-Term Security Practices
- Regularly update Junos OS to the latest patched versions.
- Implement network segmentation to restrict telnet client access.
- Conduct security awareness training to educate users on safe practices.
Patching and Updates
Software releases including 12.3R12-S13, 18.4R2, and subsequent versions have been updated to address this vulnerability.