Donato Ferrante
Application: xweb
http://in.geocities.com/shamit_bagchi
Version: 1.0
Bug: directory traversal bug
Author: Donato Ferrante
e-mail: fdonato@autistici.org
web: www.autistici.org/fdonato
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1. Description
2. The bug
3. The code
4. The fix
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1. Description:
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xweb is a free HTTP server, for Linux based systems.
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2. The bug:
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The program doesn't check for malicious patterns like "/../", so an
attacker is able to see and download all the files on the remote
system simply using a browser.
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3. The code:
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To test the vulnerability:
http://[host]/../../../../etc/passwd
or:
http://[host]/../someFile
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4. The fix:
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Vendor was contacted.
Bug will be probably fixed in the next version of xweb.
If you want, you can use my following little patch, that should fix
the bug for this version of xweb:
.
..
...
(line: 233 of server.c) pstr[i]='\0';
/* start of patch */
int d = 0,
found = 1;
for( ; d < strlen(secondstr)-1 && found == 1; d++ ) {
if( (secondstr[d] == '.') && (secondstr[d+1] == '.') )
found = 0;
}
if(found == 0)
strcpy(secondstr, "/");
/* end of patch */
...
..
.
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