{"vuid":"VU#715973","idnumber":"715973","name":"ISC BIND 8.2.2-P6 vulnerable to DoS via compressed zone transfer, aka the \"zxfr bug\"","keywords":["ISC","BIND","DoS compressed zone transfer","denial-of-service","gzip","zip","zxfr bug\""],"overview":"There is a denial-of-service vulnerability in several versions of the Internet Software Consortium's (ISC) BIND software. This vulnerability is referred to by the ISC as the \"zxfr bug.\"  It affects ISC BIND version 8.2.2, patch levels 1 through 6.","clean_desc":"Using this vulnerability, attackers on sites that are permitted to request zone transfers can force the name service daemon (named) running on vulnerable DNS servers to crash, disrupting name resolution service until the named daemon is restarted. The preconditions for this attack to succeed are as follows: A compressed zone transfer (ZXFR) request must be made from a site allowed to make any zone transfer request (not just ZXFR). A subsequent name service query of an authoritative and non-cached record must be made. The time between the attack and the crash of named may vary from system to system. This vulnerability has been discussed in public forums. The ISC has confirmed that all platforms running version 8.2.2 of the BIND software prior to patch level 7 are vulnerable to this attack.","impact":"A remote attacker can use malicious zone transfers to crash vulnerable BIND servers, resulting in a denial-of-service condition that disables name resolution service.","resolution":"Apply a patch from your vendor To address this vulnerability, the CERT/CC recommends that all users of ISC BIND upgrade to version 8.2.2-P7, which patches both VU#198355 and VU#715973. For information regarding vendor-specific versions of DNS software, please consult the Systems Affected section of this document.","workarounds":"If it is not possible to immediately upgrade systems affected by the \"zxfr bug\", the ISC recommends that users block zone transfers from untrusted hosts.","sysaffected":"","thanks":"The CERT Coordination Center thanks Mark Andrews, David Conrad, and Paul Vixie of the ISC for developing a solution and assisting in the preparation of this document. We also thank Olaf Kirch for helping us to understand the exact nature of the \"zxfr bug\" vulnerability.","author":"This document was written by Jeffrey S. Havrilla and Jeffrey P. Lanza.","public":["http://www.securityfocus.com/bid/1923","http://www.isc.org/products/BIND/bind8.html","http://www.isc.org/products/BIND/bind-security.html","http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=20546","http://www.securityfocus.com/archive/82/144170"],"cveids":["CVE-2000-0887"],"certadvisory":"CA-2000-20","uscerttechnicalalert":null,"datecreated":"2000-11-09T20:47:08Z","publicdate":"2000-11-07T00:00:00Z","datefirstpublished":"2000-11-10T16:58:55Z","dateupdated":"2001-08-08T22:18:55Z","revision":33,"vrda_d1_directreport":"","vrda_d1_population":"","vrda_d1_impact":"","cam_widelyknown":"20","cam_exploitation":"10","cam_internetinfrastructure":"19","cam_population":"18","cam_impact":"5","cam_easeofexploitation":"20","cam_attackeraccessrequired":"20","cam_scorecurrent":"33.075","cam_scorecurrentwidelyknown":"33.075","cam_scorecurrentwidelyknownexploited":"39.825","ipprotocol":"","cvss_accessvector":"","cvss_accesscomplexity":"","cvss_authentication":null,"cvss_confidentialityimpact":"","cvss_integrityimpact":"","cvss_availabilityimpact":"","cvss_exploitablity":null,"cvss_remediationlevel":"","cvss_reportconfidence":"","cvss_collateraldamagepotential":"","cvss_targetdistribution":"","cvss_securityrequirementscr":"","cvss_securityrequirementsir":"","cvss_securityrequirementsar":"","cvss_basescore":"","cvss_basevector":"","cvss_temporalscore":"","cvss_environmentalscore":"","cvss_environmentalvector":"","metric":33.075,"vulnote":null}