CVE-2021-31352

Public Exploit
SRC Series: NETCONF over SSH allows negotiation of weak ciphers

Description

An Information Exposure vulnerability in Juniper Networks SRC Series devices configured for NETCONF over SSH permits the negotiation of weak ciphers, which could allow a remote attacker to obtain sensitive information. A remote attacker with read and write access to network data could exploit this vulnerability to display plaintext bits from a block of ciphertext and obtain sensitive information. This issue affects all Juniper Networks SRC Series versions prior to 4.13.0-R6.

Remediation

Solution:

  • A hotfix has been created to resolve this issue. Contact Juniper Networks Technical Support to request the hotfix. Weak ciphers are now disabled by default. Only the following ciphers and key-exchange (KEX) algorithms are now enabled by default: • Ciphers: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com • KEX Algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1 Note: After upgrading to a fixed release, any manually configured weak ciphers or KEX algorithms for NETCONF will be retained. Administrators should reset their cipher configuration by typing: root@src# delete system services netconf ssh root@src# commit Stopping NETCONF/SSH: commit complete. root@src# set system services netconf ssh

Workaround:

  • There are no viable workarounds for this issue.

Categories

5.3
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.12%
Vendor Advisory juniper.net
Affected: Juniper Networks SRC Series
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11217 exploit patch vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-31352?
CVE-2021-31352 has been scored as a medium severity vulnerability.
How to fix CVE-2021-31352?
To fix CVE-2021-31352: A hotfix has been created to resolve this issue. Contact Juniper Networks Technical Support to request the hotfix. Weak ciphers are now disabled by default. Only the following ciphers and key-exchange (KEX) algorithms are now enabled by default: • Ciphers: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com • KEX Algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1 Note: After upgrading to a fixed release, any manually configured weak ciphers or KEX algorithms for NETCONF will be retained. Administrators should reset their cipher configuration by typing: root@src# delete system services netconf ssh root@src# commit Stopping NETCONF/SSH: commit complete. root@src# set system services netconf ssh
Is CVE-2021-31352 being actively exploited in the wild?
It is possible that CVE-2021-31352 is being exploited or will be exploited in a near future based on public information. 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-2021-31352?
CVE-2021-31352 affects Juniper Networks SRC Series.
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