CVE-2021-0278 : Security Advisory and Response
Learn about CVE-2021-0278, an Improper Input Validation vulnerability in J-Web of Juniper Networks Junos OS that allows privilege escalation to root. Understand the impact, affected versions, exploitation, and mitigation steps.
An Improper Input Validation vulnerability in J-Web of Juniper Networks Junos OS allows a locally authenticated attacker to escalate their privileges to root over the target device. Learn about the impact, affected systems, exploitation mechanism, mitigation, and prevention steps in this article.
Understanding CVE-2021-0278
This CVE highlights a privilege escalation vulnerability in Juniper Networks Junos OS J-Web interface.
What is CVE-2021-0278?
CVE-2021-0278 is an Improper Input Validation vulnerability that, if exploited, allows a locally authenticated attacker to gain root privileges on the affected device through the J-Web interface in Junos OS.
The Impact of CVE-2021-0278
The vulnerability has a CVSS base score of 8.8, indicating a high-severity issue with significant impacts on confidentiality, integrity, and availability of the system.
Technical Details of CVE-2021-0278
The following configurations are susceptible to this vulnerability:
- [system services web-management http]
- [system services web-management https]
Vulnerability Description
The vulnerability allows an authenticated attacker to escalate privileges to root on the Junos OS device through the J-Web interface.
Affected Systems and Versions
Juniper Networks Junos OS versions from 19.3R1 to 21.1R2 are affected, with specific versions vulnerable to this exploit.
Exploitation Mechanism
At the time of this report, there are no known instances of malicious exploitation, but a proof-of-concept exploit is available in the wild.
Mitigation and Prevention
If you are using an affected version of Junos OS, take immediate steps for prevention and long-term security practices.
Immediate Steps to Take
Upgrade to the patched versions released by Juniper: 19.3R2-S6, 19.3R3-S3, 19.4R3-S5, 20.1R2-S2, 20.1R3-S1, 20.2R3-S2, 20.3R3, 20.4R2-S1, 20.4R3, 21.1R1-S1, 21.1R2, 21.2R1, or newer.
Long-Term Security Practices
Consider using access lists or firewall filters to restrict access to the administrative interfaces.
Patching and Updates
Besides the fixed releases, certain not-affected versions received security enhancements as a precaution.