.. / ed
Star

Shell
File write
File read
Sudo
Limited SUID

Shell

It can be used to break out from restricted environments by spawning an interactive system shell.

```
ed
!/bin/sh
```

File write

It writes data to files, it may be used to do privileged writes or write files outside a restricted file system.

```
ed file_to_write
a
DATA
.
w
q
```

File read

It reads data from files, it may be used to do privileged reads or disclose files outside a restricted file system.

```
ed file_to_read
,p
q
```

Sudo

It runs in privileged context and may be used to access the file system, escalate or maintain access with elevated privileges if enabled on sudo.

```
sudo ed
!/bin/sh
```

Limited SUID

It runs with the SUID bit set and may be exploited to access the file system, escalate or maintain access with elevated privileges working as a SUID backdoor. If it is used to run commands it only works on systems like Debian that allow the default sh shell to run with SUID privileges.