CVE-2021-0255

Junos OS: ethtraceroute Local Privilege Escalation vulnerability in SUID binaries

Description

A local privilege escalation vulnerability in ethtraceroute of Juniper Networks Junos OS may allow a locally authenticated user with shell access to escalate privileges and write to the local filesystem as root. ethtraceroute is shipped with setuid permissions enabled and is owned by the root user, allowing local users to run ethtraceroute with root privileges. This issue affects Juniper Networks Junos OS: 15.1X49 versions prior to 15.1X49-D240; 17.3 versions prior to 17.3R3-S11, 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R2-S7; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S4; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R3-S1; 20.1 versions prior to 20.1R2, 20.1R3; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: Junos OS 15.1X49-D240, 17.3R3-S11, 17.4R3-S4, 18.1R3-S12, 18.2R3-S7, 18.4R2-S7, 19.1R1-S6, 19.1R2-S2, 19.1R3-S4, 19.3R3-S2, 19.4R3-S1, 20.1R2, 20.1R3, 20.2R2-S1, 20.2R3, 20.3R1-S1, 21.1R1, and all subsequent releases. As a proactive measure to tighten the security of other Ethernet OAM utilities, setuid was also removed from other binaries, including ethping, ethdm, ethslm and ethlm.

Workaround:

  • To reduce the risk of malicious exploitation, use access lists or firewall filters to limit CLI access to the device only from trusted, administrative networks or hosts. Additionally, limit access to the Junos OS shell to only trusted system administrators.

Categories

5.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.02%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11175 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-0255?
CVE-2021-0255 has been scored as a medium severity vulnerability.
How to fix CVE-2021-0255?
To fix CVE-2021-0255: The following software releases have been updated to resolve this specific issue: Junos OS 15.1X49-D240, 17.3R3-S11, 17.4R3-S4, 18.1R3-S12, 18.2R3-S7, 18.4R2-S7, 19.1R1-S6, 19.1R2-S2, 19.1R3-S4, 19.3R3-S2, 19.4R3-S1, 20.1R2, 20.1R3, 20.2R2-S1, 20.2R3, 20.3R1-S1, 21.1R1, and all subsequent releases. As a proactive measure to tighten the security of other Ethernet OAM utilities, setuid was also removed from other binaries, including ethping, ethdm, ethslm and ethlm.
Is CVE-2021-0255 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-0255 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-2021-0255?
CVE-2021-0255 affects Juniper Networks Junos OS.
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