From security@linux-mandrake.com Sat May 11 13:23:17 2002 From: Mandrake Linux Security Team To: bugtraq@securityfocus.com Date: 9 May 2002 16:41:48 -0000 Subject: MDKSA-2002:030 - temporary fix for netfilter information leak -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ________________________________________________________________________ Mandrake Linux Security Update Advisory ________________________________________________________________________ Package name: iptables/kernel Advisory ID: MDKSA-2002:030 Date: May 9th, 2002 Affected versions: 8.0, 8.1, 8.2 ________________________________________________________________________ Problem Description: A problem was discovered with Netfilter Network Address Translation (NAT) capabilities. It was found that iptables can leak information about how port forwarding is accomplished in unfiltered ICMP packets. When a NAT rule applies to the first packet of a connection, which subsequently causes the system to generate an ICMP error message, the ICMP error message is transmitted including the translated address. This information gives the IP address of the system to which the connection would have been forwarded had the error message not been generated, exposing information about the netfilter configuration and the network topology. There is currently no clean fix for this problem, but a fix is being worked on. In the meantime, if you use the NAT capabilities of iptables, you can protect yourself by filtering out untracked local ICMP packets using the following iptables command: iptables -A OUTPUT -m state -p icmp --state INVALID -j DROP All kernel patches from iptables < 1.2.6a are vulnerable. All kernel versions from 2.4.4 and up to (at least) 2.4.19-pre6 use a vulnerable version. Thanks to Philippe Biondi for discovering this problem. ________________________________________________________________________ References: http://online.securityfocus.com/archive/1/271530/2002-05-06/2002-05-12/0 ________________________________________________________________________ Updated Packages: None currently available. ________________________________________________________________________ Bug IDs fixed (see https://qa.mandrakesoft.com for more information): ________________________________________________________________________ To upgrade automatically, use MandrakeUpdate. The verification of md5 checksums and GPG signatures is performed automatically for you. If you want to upgrade manually, download the updated package from one of our FTP server mirrors and upgrade with "rpm -Fvh *.rpm". A list of FTP mirrors can be obtained from: http://www.mandrakesecure.net/en/ftp.php Please verify the update prior to upgrading to ensure the integrity of the downloaded package. You can do this with the command: rpm --checksig All packages are signed by MandrakeSoft for security. You can obtain the GPG public key of the Mandrake Linux Security Team from: https://www.mandrakesecure.net/RPM-GPG-KEYS Please be aware that sometimes it takes the mirrors a few hours to update. You can view other update advisories for Mandrake Linux at: http://www.mandrakesecure.net/en/advisories/ MandrakeSoft has several security-related mailing list services that anyone can subscribe to. Information on these lists can be obtained by visiting: http://www.mandrakesecure.net/en/mlist.php If you want to report vulnerabilities, please contact security@linux-mandrake.com ________________________________________________________________________ Type Bits/KeyID Date User ID pub 1024D/22458A98 2000-07-10 Linux Mandrake Security Team - -----BEGIN PGP PUBLIC KEY BLOCK----- Version: GnuPG v1.0.5 (GNU/Linux) Comment: For info see http://www.gnupg.org mQGiBDlp594RBAC2tDozI3ZgQsE7XwxurJCJrX0L5vx7SDByR5GHDdWekGhdiday L4nfUax+SeR9SCoCgTgPW1xB8vtQc8/sinJlMjp9197a2iKM0FOcPlkpa3HcOdt7 WKJqQhlMrHvRcsivzcgqjH44GBBJIT6sygUF8k0lU6YnMHj5MPc/NGWt8wCg9vKo P0l5QVAFSsHtqcU9W8cc7wMEAJzQsAlnvPXDBfBLEH6u7ptWFdp0GvbSuG2wRaPl hynHvRiE01ZvwbJZXsPsKm1z7uVoW+NknKLunWKB5axrNXDHxCYJBzY3jTeFjsqx PFZkIEAQphLTkeXXelAjQ5u9tEshPswEtMvJvUgNiAfbzHfPYmq8D6x5xOw1IySg 2e/LBACxr2UJYCCB2BZ3p508mAB0RpuLGukq+7UWiOizy+kSskIBg2O7sQkVY/Cs iyGEo4XvXqZFMY39RBdfm2GY+WB/5NFiTOYJRKjfprP6K1YbtsmctsX8dG+foKsD LLFs7OuVfaydLQYp1iiN6D+LJDSMPM8/LCWzZsgr9EKJ8NXiyrQ6TGludXggTWFu ZHJha2UgU2VjdXJpdHkgVGVhbSA8c2VjdXJpdHlAbGludXgtbWFuZHJha2UuY29t PohWBBMRAgAWBQI5aefeBAsKBAMDFQMCAxYCAQIXgAAKCRCaqNDQIkWKmK6LAKCy /NInDsaMSI+WHwrquwC5PZrcnQCeI+v3gUDsNfQfiKBvQSANu1hdulqIRgQQEQIA BgUCOtNVGQAKCRBZ5w3um0pAJJWQAKDUoL5He+mKbfrMaTuyU5lmRyJ0fwCgoFAP WdvQlu/kFjphF740XeOwtOqIRgQQEQIABgUCOu8A6QAKCRBynDnb9lq3CnpjAJ4w Pk0SEE9U4r40IxWpwLU+wrWVugCdFfSPllPpZRCiaC7HwbFcfExRmPa5AQ0EOWnn 7xAEAOQlTVY4TiNo5V/iP0J1xnqjqlqZsU7yEBKo/gZz6/+hx75RURe1ebiJ9F77 9FQbpJ9Epz1KLSXvq974rnVb813zuGdmgFyk+ryA/rTR2RQ8h+EoNkwmATzRxBXV Jb57fFQjxOu4eNjZAtfII/YXb0uyXXrdr5dlJ/3eXrcO4p0XAAMFBACCxo6Z269s +A4v8C6Ui12aarOQcCDlV8cVG9LkyatU3FNTlnasqwo6EkaP572448weJWwN6SCX Vl+xOYLiK0hL/6Jb/O9Agw75yUVdk+RMM2I4fNEi+y4hmfMh2siBv8yEkEvZjTcl 3TpkTfzYky85tu433wmKaLFOv0WjBFSikohGBBgRAgAGBQI5aefvAAoJEJqo0NAi RYqYid0AoJgeWzXrEdIClBOSW5Q6FzqJJyaqAKC0Y9YI3UFlE4zSIGjcFlLJEJGX lA== =0ahQ - -----END PGP PUBLIC KEY BLOCK----- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE82qbMmqjQ0CJFipgRAv4xAJ40tRCKf9Ccy3lQYmn6Vc00Gg8DZQCgx+kj jJYeT/SuZkd4NtuhQSvBWwg= =8OV3 -----END PGP SIGNATURE-----