ay0i

A self-replicating and mutating linux process.

How it works

Reads its own executable file
Writes out the bytes of the executable to a random filename possibly inserting mutations
Forks and execs the new executable

Mutations

There are three types of mutations that can occur:

Insertion of random byte
Substituting existing byte with random byte
Deletion of a byte

Running

Create a new user.
Create empty file of 128MB size (dd if=/dev/zero of=myfile bs=1M count=128).
Format this file with a filesystem, i.e. mkfs.ext4 myfile.
Mount this file as the home directory of the new user (mount -t ext4 -o loop myfile /home/newuser)
Set limits for newuser, in Ubuntu this can be done by creating the file /etc/security/limits.d/myuser.conf with the following example content:

newuser hard nice 19 newuser hard priority 100 newuser hard cpu 1 newuser hard nproc 600 ```

These settings help your computer to stay responsive during the experiment. If you switch to newuser via the su command then you also need to add the following line to the file /etc/pam.d/su:

```
session required pam_limits.so
```

Compile the program.
Run program under the new user account.

Risks

Anything could happen, but what generally happens is that (without user limits) it behaves like a forkbomb so that your system will become unresponsive and you may need to reboot your computer. It will also fill the disk with random files of itself.

System requirements

x86-64 processor and linux environment
kernel >= 3.17 for the getrandom syscall

TODO

Write a daemon or a cronjob that kills long-running processes of the executing user. This will regulate the population of the processes.