CVE-2021-0269

Junos OS: J-Web can be compromised through reflected client-side HTTP parameter pollution attacks.

Description

The improper handling of client-side parameters in J-Web of Juniper Networks Junos OS allows an attacker to perform a number of different malicious actions against a target device when a user is authenticated to J-Web. An attacker may be able to supersede existing parameters, including hardcoded parameters within the HTTP/S session, access and exploit variables, bypass web application firewall rules or input validation mechanisms, and otherwise alter and modify J-Web's normal behavior. An attacker may be able to transition victims to malicious web services, or exfiltrate sensitive information from otherwise secure web forms. This issue affects: Juniper Networks Junos OS: All versions prior to 17.4R3-S3; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R3-S6; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R3-S6; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R3-S1; 19.3 versions prior to 19.3R3-S1; 19.4 versions prior to 19.4R2-S2, 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: 17.4R3-S3, 18.1R3-S12, 18.2R3-S6, 18.3R3-S4, 18.4R3-S6, 19.1R3-S4, 19.2R3-S1, 19.3R3-S1, 19.4R2-S2, 19.4R3, 20.1R2, 20.2R2, 20.3R1, and all subsequent releases.

Workaround:

  • To reduce the risk of exploitation utilize common security BCPs to limit the exploitable surface by limiting access to network and device to trusted systems, administrators, networks and hosts. Access the J-Web service from trusted hosts which may not be compromised by cross-site scripting attacks, for example, deploying jump hosts with no internet access. Alternatively, disable J-Web.

Category

8.8
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.38%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11160 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-0269?
CVE-2021-0269 has been scored as a high severity vulnerability.
How to fix CVE-2021-0269?
To fix CVE-2021-0269: The following software releases have been updated to resolve this specific issue: 17.4R3-S3, 18.1R3-S12, 18.2R3-S6, 18.3R3-S4, 18.4R3-S6, 19.1R3-S4, 19.2R3-S1, 19.3R3-S1, 19.4R2-S2, 19.4R3, 20.1R2, 20.2R2, 20.3R1, and all subsequent releases.
Is CVE-2021-0269 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-0269 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-0269?
CVE-2021-0269 affects Juniper Networks Junos OS.
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