Systemd, the Linux system and service manager who has largely replaced init as the master Linux startup and control program, have always had their critics. Now, with Qualy’s discovery of a new systemd security flaw, systemd will have fewer friends. Successful exploitation of this latest vulnerability enables all unprivileged users to cause denial of service through a core panic.
In one sentence, “it’s bad, it’s very bad.”
As Bharat Jogi, Qualy’s Senior Vulnerability and Signatures Manager, wrote: “Given the breadth of the attack surface for this vulnerability, Qualy̵
Systemd is used in almost all modern Linux distributions. This special security hole appeared in the system code in April 2015.
It works by enabling attackers to abuse the alloca () function in a way that will result in memory corruption. This in turn allows a hacker to crash the systemd and thus the entire operating system. In practice, this can be done by a local attacker mounting a file system on a very long road. This causes too much memory to be used in the system stack, resulting in a system crash.
That’s the bad news. The good news is that Red Hat Product Security and systemd developers have immediately patched the hole.
There is no way to remedy this problem. Although it is not present in all current Linux distros, you will find it in most distros such as Debian 10 (Buster) and its relatives such as Ubuntu and Mint. Therefore, if you appreciate keeping your computers running, you should patch the systemd version as soon as possible. You will be glad you did.