Race condition in signal handling of procmail 3.20 and earlier, when running setuid, allows local users to cause a denial of service or gain root privileges by sending a signal while a signal handling routine is already running.
This is a vulnerability exploitable with only local access requires the attacker to have either
physical access to the vulnerable system or a local (shell) account. Examples of locally
exploitable vulnerabilities are peripheral attacks such as Firewire/USB DMA attacks, and
local privilege escalations (e.g., sudo).
Specialized access conditions exist. For example,
in most configurations, the attacking party must already have elevated privileges or spoof additional systems
in addition to the attacking system (e.g., DNS hijacking).
The attack depends on social engineering methods that would be easily detected by knowledgeable people.
For example, the victim must perform several suspicious or atypical actions.
The vulnerable configuration is seen very rarely in practice.
If a race condition exists, the window is very narrow.
Authentication is not required to access and exploit the vulnerability.
There is total information disclosure, resulting in all system files being revealed. The
attacker is able to read all of the system's data (memory, files, etc.).
There is a total compromise of system integrity. There is a complete loss of system
protection, resulting in the entire system being compromised. The attacker is able to
modify any files on the target system.
There is a total shutdown of the affected resource. The attacker can render the
resource completely unavailable.