Product Code Database
In computing, a fork bomb (also called rabbit virus) is a denial-of-service (DoS) attack wherein a process continually replicates itself to deplete available system resources, slowing down or crashing the system due to resource starvation.
In Unix-like operating systems, fork bombs are generally written to use the fork system call. As forked processes are also copies of the first program, once they resume execution from the next address at the frame pointer, they continue forking endlessly within their own copy of the same infinite loop. this has the effect of causing an exponential growth in processes. As modern Unix generally use a copy-on-write resource management technique when forking new processes, (2025). 9780070611948, McGraw-Hill Higher Education. ISBN 9780070611948 a fork bomb generally will not saturate such a system's memory.
Microsoft Windows operating systems do not have an equivalent functionality to the Unix fork system call; a fork bomb on such an operating system must therefore create a new process instead of forking from an existing one, such as with Batch file echo %0^|%0 > $_.cmd & $_. In this batch script, %0|%0 is written to $_.cmd, which is then executed by & $_.
A classic example of a fork bomb is one written in Unix shell :(){ :|:& };:, possibly dating back to 1999, which can be more easily understood as
fork | fork &
}
fork
The code using a colon & as the function name is not valid in a shell as defined by POSIX, which only permits alphanumericals and underscores in function names. However, its usage is allowed in GNU Bash as an extension.
|
|
