CVE-2021-31373 : Security Advisory and Response

A persistent Cross-Site Scripting (XSS) vulnerability in Juniper Networks Junos OS on SRX Series, J-Web interface may allow a remote authenticated user to inject persistent and malicious scripts. This vulnerability could be exploited by an attacker to steal sensitive data from web administration sessions or hijack active user sessions for administrative actions across affected Junos OS versions.

Understanding CVE-2021-31373

This CVE identifies a persistent XSS vulnerability affecting Juniper Networks Junos OS running on SRX Series devices.

What is CVE-2021-31373?

The CVE-2021-31373 vulnerability is a persistent XSS issue on Juniper Networks Junos OS devices. It enables a remote authenticated attacker to inject harmful scripts into the J-Web interface, potentially leading to data theft and session hijacking.

The Impact of CVE-2021-31373

The impact of this vulnerability is significant, as it exposes affected devices to malicious script injections that can compromise data confidentiality, integrity, and availability through unauthorized access and session manipulation.

Technical Details of CVE-2021-31373

This section provides a detailed overview of the vulnerability, affected systems, and exploitation mechanism.

Vulnerability Description

The XSS vulnerability in Juniper Networks Junos OS allows authenticated attackers to inject persistent scripts through the J-Web interface, posing a threat to sensitive data and user sessions.

Affected Systems and Versions

Juniper Networks Junos OS versions 18.2 to 20.3 running on SRX Series devices are affected by this vulnerability.

Exploitation Mechanism

Remote authenticated attackers can exploit this vulnerability to inject malicious scripts into the J-Web interface, potentially leading to data theft and session hijacking.

Mitigation and Prevention

To secure systems against CVE-2021-31373, immediate actions and long-term security practices need to be implemented.

Immediate Steps to Take

Reduce the risk of exploitation by using access lists or firewall filters to restrict access to trusted networks. Alternatively, disable the J-Web interface to mitigate the vulnerability.

Long-Term Security Practices

Regularly update systems with the patched software releases provided by Juniper Networks to address this specific issue and enhance overall device security.

Patching and Updates

Juniper Networks has released software updates including versions 18.2R3-S8, 18.3R3-S5, 18.4R3-S8, 19.1R3-S5, 19.2R1-S7, 19.2R3-S3, 19.3R2-S6, 19.3R3-S3, 19.4R1-S4, 19.4R2-S4, 19.4R3-S3, 20.1R2-S2, 20.1R3, 20.2R3-S1, 20.3R2-S1, 20.3R3, 20.4R1, and subsequent releases.