OpenSSH 5.2 Secured and Tuned
Even though the OpenSSH project emphasizes that the focus of 5.2 is bug fixes to the 5.1 version, 5.2 does contain some notable enhancements.
Security-wise the new OpenSSH version replaces cipher block chaining (CBC) mode as the default cipher order with the Advanced Encryption Standard (AES) Counter (CTR) mode to remove the susceptibility to "Plaintext Recovery Attack Against SSH." The software also adds other countermeasures to these attacks, as reported in CPNI Vulnerability Advisory SSH 957037. Last November it became clear that many versions of OpenSSH exposed up to 32 bits of plaintext ciphertext to attackers when the default CBC mode was in use. The solution in 5.2 was to read the maximum supported packet length instead of terminating the connection, thereby eliminating the leaks that allowed the plaintext recovery attacks.
Compared to OpenSSH 5.1, the updated version provides further command line options and minor functional enhancements. For example, the ssh -y option redirects logging to syslog and dynamic port forwarding was improved. The release changelog includes the list of fixed bugs.
OpenSSH emanates from the OpenBSD project, where a separate team focuses on OpenSSH's portability to different systems. The mirrors with the portable versions also include diffs against the OpenBSD source.
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Linux Kernel 6.17 Drops bcachefs
After a clash over some late fixes and disagreements between bcachefs's lead developer and Linus Torvalds, bachefs is out.
-
ONLYOFFICE v9 Embraces AI
Like nearly all office suites on the market (except LibreOffice), ONLYOFFICE has decided to go the AI route.
-
Two Local Privilege Escalation Flaws Discovered in Linux
Qualys researchers have discovered two local privilege escalation vulnerabilities that allow hackers to gain root privileges on major Linux distributions.
-
New TUXEDO InfinityBook Pro Powered by AMD Ryzen AI 300
The TUXEDO InfinityBook Pro 14 Gen10 offers serious power that is ready for your business, development, or entertainment needs.
-
Danish Ministry of Digital Affairs Transitions to Linux
Another major organization has decided to kick Microsoft Windows and Office to the curb in favor of Linux.
-
Linux Mint 20 Reaches EOL
With Linux Mint 20 at its end of life, the time has arrived to upgrade to Linux Mint 22.
-
TuxCare Announces Support for AlmaLinux 9.2
Thanks to TuxCare, AlmaLinux 9.2 (and soon version 9.6) now enjoys years of ongoing patching and compliance.
-
Go-Based Botnet Attacking IoT Devices
Using an SSH credential brute-force attack, the Go-based PumaBot is exploiting IoT devices everywhere.
-
Plasma 6.5 Promises Better Memory Optimization
With the stable Plasma 6.4 on the horizon, KDE has a few new tricks up its sleeve for Plasma 6.5.
-
KaOS 2025.05 Officially Qt5 Free
If you're a fan of independent Linux distributions, the team behind KaOS is proud to announce the latest iteration that includes kernel 6.14 and KDE's Plasma 6.3.5.