Deprecated ssh cryptographic settings vulnerability linux. 2 and are already used by default if the client and server support them. These have been supported since OpenSSH 7. In Security Scan it is severity 4 vulnerability. The target is using deprecated SSH cryptographic settings to communicate. Aug 10, 2022 · The SSH protocol (Secure Shell) is a method for secure remote login from one computer to another. Jul 13, 2020 · The test shows the following vulnerability "Deprecated SSH Cryptographic Settings" within SSH configuration with the following impact "A man-in-the-middle attacker may be able to exploit this vulnerability to record the communication to decrypt the session key and even the messages" . May 16, 2023 · In this article discuss about Disable diffie-hellman-group1-sha1 for SSH in Linux Operating System. After that, we’ll eliminate the underlying vulnerability by configuring SSH parameters and cryptographic policies. The target is using deprecated SSH cryptographic settings to communicate. Prerequisites To use SSH to communicate with GitLab, you need: The OpenSSH client, which comes pre-installed on GNU/Linux, macOS, and Windows 10. How to disable the diffie-hellman-group1-sha1 Key Exchange Algorithm used in SSH? A Red Hat subscription provides unlimited access to our knowledgebase, tools, and much more. 4 Knowledgebase article on the Red Hat Customer Portal for more information. Since 2011, SHA1 has been deprecated by the National Institute of Standards and Technology (NIST) and is considered cryptographically weak. A man-in-the-middle attacker could use this vulnerability to record the communication and decrypt the session key and messages. Dec 26, 2024 · A Qualys scan may flag the use of the SHA1 algorithm in SSH configurations as a deprecated setting, indicating potential vulnerabilities. RC4 cipher (arcfour, arcfour128, arcfour256): Qualys Title: Deprecated SSH Cryptographic Settings This is an SSH related vulnerability and indicates that the target is using deprecated SSH cryptographic settings to communicate. For details, see Asymmetric cryptography, also known as public-key cryptography. Jul 31, 2025 · This article explains the detection logic behind QID 38739, outlines why this is not a vendor-specific vulnerability, and provides guidance for confirmation through PCAP analysis and manual verification. Jan 2, 2023 · In this article, we discuss the Deprecated SSH Cryptographic Settings in Linux. SSH version 6. However we have a network vunerability scanner that keeps alerting us on the following: 1) Deprecated SSH Cryptographic settings 2) SSH Server Public Key too small Does anyone know how I can fix th These algorithms have the advantage of using the same key type as "ssh-rsa" but use the safe SHA-2 hash algorithms. Then, we’ll learn the scenarios behind a successful exploit. In security scans like Tripwire, it is found to be a vulnerability in Centos/RHEL Machine as explained below. Vulnerability : Deprecated SSH Cryptographic Settings QID: 38739 THREAT: The SSH protocol (Secure Shell) is a method for secure remote login from one computer to another. Jan 2, 2023 · To communicate, the target supports deprecated SSH cryptographic settings. Visit Red Hat official page for more information about deprecated functionality. Jun 5, 2024 · In this tutorial, we demonstrate how to mitigate the Terrapin SSH attack. During security scans, one of the security vulnerabilities that can be found is deprecated SSH cryptographic settings. The SSH protocol (Secure Shell) is a method for securing remote login from one computer to another but the target may be using deprecated SSH cryptographic settings to communicate. Nov 30, 2023 · These are considered uncommon and deprecated due to vulnerabilities when compared to newer cipher chaining modes such as CTR or GCM. . Earlier versions used an MD5 signature, which is not secure. Vulnerability scanner detected one of the following in a RHEL-based system: Deprecated SSH Cryptographic Settings --truncated-- key exchange diffie-hellman-group1-sha1 Disable weak Key Exchange Answer As per the QID, select the Solution KB for the ONTAP 9 related Qualys Vulnerability scanner results: Jan 9, 2020 · Folks, We have a couple of Nexus devices and IOS devices on very recent codes. Aug 26, 2025 · After applying crypto-policy changes or customizing your SSH configuration, it’s essential to confirm that the weak algorithms are no longer accepted by the server. "Type Name key exchange diffie-hellman-group1-sha1". 5 or later. 2. Initially, we’ll study the attack and the vulnerability scanning process. See the Enhancing the Security of the Operating System with Cryptography Changes in Red Hat Enterprise Linux 7. bgyrnsla bhiaqg kupscc wnhn epsnz bveix yravkv axe imt qvlk