diff --git a/doc/rfc/index b/doc/rfc/index index 400da4cc57..fb72ccc314 100644 --- a/doc/rfc/index +++ b/doc/rfc/index @@ -90,4 +90,5 @@ Secret Key Transaction Authentication for DNS (GSS-TSIG) 3655: Redefinition of DNS Authenticated Data (AD) bit 3658: Delegation Signer (DS) Resource Record (RR) +3833: Threat Analysis of the Domain Name System (DNS) 3845: DNS Security (DNSSEC) NextSECure (NSEC) RDATA Format diff --git a/doc/draft/draft-ietf-dnsext-dns-threats-07.txt b/doc/rfc/rfc3833.txt similarity index 68% rename from doc/draft/draft-ietf-dnsext-dns-threats-07.txt rename to doc/rfc/rfc3833.txt index 15217dad2c..8ce4d34e34 100644 --- a/doc/draft/draft-ietf-dnsext-dns-threats-07.txt +++ b/doc/rfc/rfc3833.txt @@ -1,38 +1,27 @@ + + + + Network Working Group D. Atkins -draft-ietf-dnsext-dns-threats-07.txt IHTFP Consulting - R. Austein +Request for Comments: 3833 IHTFP Consulting +Category: Informational R. Austein ISC - April 2004 + August 2004 - Threat Analysis of the Domain Name System + Threat Analysis of the Domain Name System (DNS) +Status of this Memo -Status of this document + This memo provides information for the Internet community. It does + not specify an Internet standard of any kind. Distribution of this + memo is unlimited. - This document is an Internet-Draft and is in full conformance with - all provisions of Section 10 of RFC 2026. +Copyright Notice - Internet-Drafts are working documents of the Internet Engineering - Task Force (IETF), its areas, and its working groups. Note that - other groups may also distribute working documents as Internet- - Drafts. - - Internet-Drafts are draft documents valid for a maximum of six months - and may be updated, replaced, or obsoleted by other documents at any - time. It is inappropriate to use Internet-Drafts as reference - material or to cite them other than as "work in progress." - - The list of current Internet-Drafts can be accessed at - - - The list of Internet-Draft Shadow Directories can be accessed at - - - Distribution of this document is unlimited. Please send comments to - the Namedroppers mailing list . + Copyright (C) The Internet Society (2004). Abstract @@ -46,16 +35,6 @@ Abstract doing so, attempts to measure to what extent (if any) DNSSEC is a useful tool in defending against these threats. - - - - - -Atkins & Austein Expires 9 October 2004 [Page 1] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - 1. Introduction The earliest organized work on DNSSEC within the IETF was an open @@ -74,6 +53,13 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 authentication of DNS clients and servers as a basis for access control, this work was also ruled out of scope for DNSSEC per se. + + +Atkins & Austein Informational [Page 1] + +RFC 3833 DNS Threat Analysis August 2004 + + - Backwards compatibility and co-existence with "insecure DNS" was listed as an explicit requirement. @@ -98,20 +84,12 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 While it may seem a bit strange to publish the threat analysis a decade after starting work on the protocol designed to defend against - it, that is nevertheless what this note attempts to do. Better late - than never. + it, that is, nevertheless, what this note attempts to do. Better + late than never. This note assumes that the reader is familiar with both the DNS and with DNSSEC, and does not attempt to provide a tutorial on either. The DNS documents most relevant to the subject of this note are: - - - -Atkins & Austein Expires 9 October 2004 [Page 2] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - [RFC1034], [RFC1035], section 6.1 of [RFC1123], [RFC2181], [RFC2308], [RFC2671], [RFC2845], [RFC2930], [RFC3007], and [RFC2535]. @@ -127,6 +105,17 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 as zone transfers and dynamic update requests), and perhaps should be changed in a future revision of this note. + + + + + + +Atkins & Austein Informational [Page 2] + +RFC 3833 DNS Threat Analysis August 2004 + + 2. Known Threats There are several distinct classes of threats to the DNS, most of @@ -150,37 +139,39 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 may just be a means to an end for the attacker: the attacker might even choose to return the correct result in the answer section of a reply message while using other parts of the message to set the stage - for something more complicated, for example, a name-based attack (see - below). + for something more complicated, for example, a name chaining attack + (see section 2.3). While it certainly would be possible to sign DNS messages using a channel security mechanism such as TSIG or IPsec, or even to encrypt - them using IPsec, this would not be a very good solution. First, - this approach would impose a fairly high processing cost per DNS - message, as well as a very high cost associated with establishing and - maintaining bilateral trust relationships between all the parties - that might be involved in resolving any particular query. For - - - -Atkins & Austein Expires 9 October 2004 [Page 3] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - - heavily used name servers (such as the servers for the root zone), - this cost would almost certainly be prohibitively high. Even more - important, however, is that the underlying trust model in such a - design would be wrong, since at best it would only provide a hop-by- - hop integrity check on DNS messages and would not provide any sort of - end-to-end integrity check between the producer of DNS data (the zone - administrator) and the consumer of DNS data (the application that - triggered the query). + them using IPsec, this would not be a very good solution for + interception attacks. First, this approach would impose a fairly + high processing cost per DNS message, as well as a very high cost + associated with establishing and maintaining bilateral trust + relationships between all the parties that might be involved in + resolving any particular query. For heavily used name servers (such + as the servers for the root zone), this cost would almost certainly + be prohibitively high. Even more important, however, is that the + underlying trust model in such a design would be wrong, since at best + it would only provide a hop-by-hop integrity check on DNS messages + and would not provide any sort of end-to-end integrity check between + the producer of DNS data (the zone administrator) and the consumer of + DNS data (the application that triggered the query). By contrast, DNSSEC (when used properly) does provide an end-to-end data integrity check, and is thus a much better solution for this class of problems during basic DNS lookup operations. + + + + + +Atkins & Austein Informational [Page 3] + +RFC 3833 DNS Threat Analysis August 2004 + + TSIG does have its place in corners of the DNS protocol where there's a specific trust relationship between a particular client and a particular server, such as zone transfer, dynamic update, or a @@ -216,14 +207,6 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 By itself, ID guessing is not enough to allow an attacker to inject bogus data, but combined with knowledge (or guesses) about QNAMEs and - - - -Atkins & Austein Expires 9 October 2004 [Page 4] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - QTYPEs for which a resolver might be querying, this leaves the resolver only weakly defended against injection of bogus responses. @@ -234,6 +217,17 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 because the victim is responding (in a predictable way) to some third party action known to the attacker. + + + + + + +Atkins & Austein Informational [Page 4] + +RFC 3833 DNS Threat Analysis August 2004 + + This attack is both more and less difficult for the attacker than the simple interception attack described above: more difficult, because the attack only works when the attacker guesses correctly; less @@ -242,29 +236,29 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 In most other respects, this attack is similar to a packet interception attack. A resolver that checks DNSSEC signatures will - be able to detect the forged response; resolvers that do not - themselves perform DNSSEC signature checking should use TSIG or some + be able to detect the forged response; resolvers that do not perform + DNSSEC signature checking themselves should use TSIG or some equivalent mechanism to ensure the integrity of their communication - with a recursing name server that does perform DNSSEC signature + with a recursive name server that does perform DNSSEC signature checking. 2.3. Name Chaining Perhaps the most interesting class of DNS-specific threats are the - name chaining attacks. These are a subset of a larger class of name- - based attacks, sometimes called "cache poisoning" attacks. Most - name-based attacks can be at least partially mitigated by the long- - standing defense of checking RRs in response messages for relevance - to the original query, but such defenses do not catch name chaining - attacks. There are several variations on the basic attack, but what - they all have in common is that they all involve DNS RRs whose RDATA - portion (right hand side) includes a DNS name (or, in a few cases, - something that is not a DNS name but which directly maps to a DNS - name). Any such RR is, at least in principle, a hook that lets an - attacker feed bad data into a victim's cache, thus potentially - subverting subsequent decisions based on DNS names. + name chaining attacks. These are a subset of a larger class of + name-based attacks, sometimes called "cache poisoning" attacks. Most + name-based attacks can be partially mitigated by the long-standing + defense of checking RRs in response messages for relevance to the + original query, but such defenses do not catch name chaining attacks. + There are several variations on the basic attack, but what they all + have in common is that they all involve DNS RRs whose RDATA portion + (right hand side) includes a DNS name (or, in a few cases, something + that is not a DNS name but which directly maps to a DNS name). Any + such RR is, at least in principle, a hook that lets an attacker feed + bad data into a victim's cache, thus potentially subverting + subsequent decisions based on DNS names. - The worst examples in this class of RRs are CNAME, NS, and DNAME RRs, + The worst examples in this class of RRs are CNAME, NS, and DNAME RRs because they can redirect a victim's query to a location of the attacker's choosing. RRs like MX and SRV are somewhat less dangerous, but in principle they can also be used to trigger further @@ -272,14 +266,6 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 such as A or AAAA don't have DNS names in their RDATA, but since the IN-ADDR.ARPA and IP6.ARPA trees are indexed using a DNS encoding of IPv4 and IPv6 addresses, these record types can also be used in a - - - -Atkins & Austein Expires 9 October 2004 [Page 5] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - name chaining attack. The general form of a name chaining attack is something like this: @@ -290,6 +276,14 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 using this query as a means to inject false information about some other name). + + + +Atkins & Austein Informational [Page 5] + +RFC 3833 DNS Threat Analysis August 2004 + + - Attacker injects response, whether via packet interception, query guessing, or by being a legitimate name server that's involved at some point in the process of answering the query that the victim @@ -328,25 +322,27 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 a link to a 1x1-pixel "web bug" graphic in a piece of Text/HTML mail to the victim. If the victim's mail reading program attempts to follow such a link, the result will be a DNS query for a name chosen - - - -Atkins & Austein Expires 9 October 2004 [Page 6] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - by the attacker. DNSSEC should provide a good defense against most (all?) variations on this class of attack. By checking signatures, a resolver can determine whether the data associated with a name really was inserted - by the delegated authority for that portion of the DNS name space - (more precisely, a resolver can determine whether the entity that + by the delegated authority for that portion of the DNS name space. + More precisely, a resolver can determine whether the entity that injected the data had access to an allegedly secret key whose + + + + + +Atkins & Austein Informational [Page 6] + +RFC 3833 DNS Threat Analysis August 2004 + + corresponding public key appears at an expected location in the DNS name space with an expected chain of parental signatures that start - with a public key of which the resolver has prior knowledge). + with a public key of which the resolver has prior knowledge. DNSSEC signatures do not cover glue records, so there's still a possibility of a name chaining attack involving glue, but with DNSSEC @@ -365,15 +361,16 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 PPP options. Besides accidental betrayal of this trust relationship (via server bugs, successful server break-ins, etc), the server itself may be configured to give back answers that are not what the - user would expect (whether in an honest attempt to help the user or - to further some other goal such as furthering a business partnership - between the ISP and some third party). + user would expect, whether in an honest attempt to help the user or + to promote some other goal such as furthering a business partnership + between the ISP and some third party. This problem is particularly acute for frequent travelers who carry - their own equipment and expect it to work in much the same way no - matter which network it's plugged into at any given moment (and no - matter what brand of middle boxes a particular hotel chain might have - installed when adding network drops in every guest room...). + their own equipment and expect it to work in much the same way + wherever they go. Such travelers need trustworthy DNS service + without regard to who operates the network into which their equipment + is currently plugged or what brand of middle boxes the local + infrastructure might use. While the obvious solution to this problem would be for the client to choose a more trustworthy server, in practice this may not be an @@ -384,14 +381,6 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 prevent the client host from being able to run an iterative resolver even if the owner of the client machine is willing and able to do so. Thus, while the initial source of this problem is not a DNS protocol - - - -Atkins & Austein Expires 9 October 2004 [Page 7] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - attack per se, this sort of betrayal is a threat to DNS clients, and simply switching to a different recursive name server is not an adequate defense. @@ -399,6 +388,14 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 Viewed strictly from the DNS protocol standpoint, the only difference between this sort of betrayal and a packet interception attack is that in this case the client has voluntarily sent its request to the + + + +Atkins & Austein Informational [Page 7] + +RFC 3833 DNS Threat Analysis August 2004 + + attacker. The defense against this is the same as with a packet interception attack: the resolver must either check DNSSEC signatures itself or use TSIG (or equivalent) to authenticate the server that it @@ -413,8 +410,8 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 that is doing work on its behalf and wants to check the DNSSEC signatures itself, the resolver really does need to have independent knowledge of the DNSSEC public key(s) it needs in order to perform - the check (usually the public key for the root zone, but in some - cases knowledge of additional keys may also be appropriate). + the check. Usually the public key for the root zone is enough, but + in some cases knowledge of additional keys may also be appropriate. It is difficult to escape the conclusion that a properly paranoid resolver must always perform its own signature checking, and that @@ -440,27 +437,26 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 Much discussion has taken place over the question of authenticated denial of domain names. The particular question is whether there is a requirement for authenticating the non-existence of a name. The - - - -Atkins & Austein Expires 9 October 2004 [Page 8] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - issue is whether the resolver should be able to detect when an attacker removes RRs from a response. General paranoia aside, the existence of RR types whose absence causes an action other than immediate failure (such as missing MX and SRV RRs, which fail over to A RRs) constitutes a real threat. - Arguably, in some cases, even the immediate failure of a missing RR - might be considered a problem. The question remains: how serious is - this threat? Clearly the threat does exist; general paranoia says - that some day it'll be on the front page of some major newspaper, - even if we cannot conceive of a plausible scenario involving this - attack today. This implies that some mitigation of this risk is - required. + Arguably, in some cases, even the absence of an RR might be + + + +Atkins & Austein Informational [Page 8] + +RFC 3833 DNS Threat Analysis August 2004 + + + considered a problem. The question remains: how serious is this + threat? Clearly the threat does exist; general paranoia says that + some day it'll be on the front page of some major newspaper, even if + we cannot conceive of a plausible scenario involving this attack + today. This implies that some mitigation of this risk is required. Note that it's necessary to prove the non-existence of applicable wildcard RRs as part of the authenticated denial mechanism, and that, @@ -496,25 +492,27 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 applicable). Note that this makes the wildcard mechanisms dependent upon the - - - -Atkins & Austein Expires 9 October 2004 [Page 9] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - authenticated denial mechanism described in the previous section. DNSSEC includes mechanisms along the lines described above, which make it possible for a resolver to verify that a name server applied the wildcard expansion rules correctly when generating an answer. + + + + + +Atkins & Austein Informational [Page 9] + +RFC 3833 DNS Threat Analysis August 2004 + + 3. Weaknesses of DNSSEC DNSSEC has some problems of its own: - - DNSSEC is complex to implement, and includes some nasty edge cases + - DNSSEC is complex to implement and includes some nasty edge cases at the zone cuts that require very careful coding. Testbed experience to date suggests that trivial zone configuration errors or expired keys can cause serious problems for a DNSSEC-aware @@ -530,10 +528,10 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 and in some cases will also need to issue further queries. This increased workload will also increase the time it takes to get an answer back to the original DNS client, which is likely to trigger - both timeouts and re-queries in some cases. (Arguably, many - current DNS clients are already too impatient even before taking - the further delays that DNSSEC will impose into account, but that's - a separate topic for another document....) + both timeouts and re-queries in some cases. Arguably, many current + DNS clients are already too impatient even before taking the + further delays that DNSSEC will impose into account, but that topic + is beyond the scope of this note. - Like DNS itself, DNSSEC's trust model is almost totally hierarchical. While DNSSEC does allow resolvers to have special @@ -552,20 +550,20 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 the validating resolver and the entity creating the DNSSEC signatures. Prior to DNSSEC, all time-related actions in DNS could be performed by a machine that only knew about "elapsed" or - - - -Atkins & Austein Expires 9 October 2004 [Page 10] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - "relative" time. Because the validity period of a DNSSEC signature is based on "absolute" time, a validating resolver must have the same concept of absolute time as the zone signer in order to determine whether the signature is within its validity period or has expired. An attacker that can change a resolver's opinion of the current absolute time can fool the resolver using expired + + + +Atkins & Austein Informational [Page 10] + +RFC 3833 DNS Threat Analysis August 2004 + + signatures. An attacker that can change the zone signer's opinion of the current absolute time can fool the zone signer into generating signatures whose validity period does not match what the @@ -578,24 +576,23 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 to whether the authenticated denial mechanism is completely airtight and whether it would be worthwhile to optimize the authenticated denial mechanism for the common case in which - wildcards are not present in a zone, but the main problem is just - the inherent complexity of the wildcard mechanism itself. This - complexity probably makes the code for generating and checking + wildcards are not present in a zone. However, the main problem is + just the inherent complexity of the wildcard mechanism itself. + This complexity probably makes the code for generating and checking authenticated denial attestations somewhat fragile, but since the alternative of giving up wildcards entirely is not practical due to - widespread use, we are going to have to live with wildcards, and - the question just becomes one of whether or not the proposed + widespread use, we are going to have to live with wildcards. The + question just becomes one of whether or not the proposed optimizations would make DNSSEC's mechanisms more or less fragile. - Even with DNSSEC, the class of attacks discussed in section 2.4 is not easy to defeat. In order for DNSSEC to be effective in this case, it must be possible to configure the resolver to expect - certain categories of DNS records to be signed, which may require + certain categories of DNS records to be signed. This may require manual configuration of the resolver, especially during the initial DNSSEC rollout period when the resolver cannot reasonably expect the root and TLD zones to be signed. - 4. Topics for Future Work This section lists a few subjects not covered above which probably @@ -604,17 +601,10 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 4.1. Interactions With Other Protocols The above discussion has concentrated exclusively on attacks within - the boundaries of the DNS protocol itself, since those are the - problems against (some of) which DNSSEC was intended to protect. - There are, however, other potential problems at the boundaries where - DNS interacts with other protocols. - - - -Atkins & Austein Expires 9 October 2004 [Page 11] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - + the boundaries of the DNS protocol itself, since those are (some of) + the problems against which DNSSEC was intended to protect. There + are, however, other potential problems at the boundaries where DNS + interacts with other protocols. 4.2. Securing DNS Dynamic Update @@ -622,6 +612,14 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 with DNSSEC. Dynamic update of a non-secure zone can use TSIG to authenticate the updating client to the server. While TSIG does not scale very well (it requires manual configuration of shared keys + + + +Atkins & Austein Informational [Page 11] + +RFC 3833 DNS Threat Analysis August 2004 + + between the DNS name server and each TSIG client), it works well in a limited or closed environment such as a DHCP server updating a local DNS name server. @@ -634,10 +632,10 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 the changes to the zone. This means that either: a) The updating client must have access to a zone-signing key in - order to sign the update before sending it to the server, or + order to sign the update before sending it to the server, or b) The DNS name server must have access to an online zone-signing key - in order to sign the update. + in order to sign the update. In either case, a zone-signing key must be available to create signed RRsets to place in the updated zone. The fact that this key must be @@ -661,17 +659,6 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 Scaling properties of the key management problem here are a particular concern that needs more study. - - - - - - -Atkins & Austein Expires 9 October 2004 [Page 12] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - - 4.3. Securing DNS Zone Replication As discussed in previous sections, DNSSEC per se attempts to provide @@ -681,19 +668,27 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 protocol. For purposes of replicating entire DNS zones, however, DNSSEC does not provide object security, because zones include unsigned NS RRs and glue at delegation points. Use of TSIG to + + + +Atkins & Austein Informational [Page 12] + +RFC 3833 DNS Threat Analysis August 2004 + + protect zone transfer (AXFR or IXFR) operations provides "channel security", but still does not provide object security for complete - zones, so the trust relationships involved in zone transfer are still + zones. The trust relationships involved in zone transfer are still very much a hop-by-hop matter of name server operators trusting other - name server operators, rather than an end-to-end matter of name - server operators trusting zone administrators. + name server operators rather than an end-to-end matter of name server + operators trusting zone administrators. Zone object security was not an explicit design goal of DNSSEC, so failure to provide this service should not be a surprise. Nevertheless, there are some zone replication scenarios for which this would be a very useful additional service, so this seems like a useful area for future work. In theory it should not be difficult to - zone object security as a backwards compatible enhancement to the + add zone object security as a backwards compatible enhancement to the existing DNSSEC model, but the DNSEXT WG has not yet discussed either the desirability of or the requirements for such an enhancement. @@ -708,29 +703,38 @@ Security Considerations The authors believe that deploying DNSSEC will help to address some, but not all, of the known threats to the DNS. -IANA Considerations - - None. - Acknowledgments - This note is based both previous published works by others and on a - number of discussions both public and private over a period of many - years, but particular thanks go to Jaap Akkerhuis, Steve Bellovin, - Dan Bernstein, Randy Bush, Steve Crocker, Olafur Gudmundsson, Russ - Housley, Rip Loomis, Allison Mankin, Paul Mockapetris, Thomas Narten - Mans Nilsson, Pekka Savola, Paul Vixie, Xunhua Wang, and any other + This note is based both on previous published works by others and on + a number of discussions both public and private over a period of many + years, but particular thanks go to + + Jaap Akkerhuis, + Steve Bellovin, + Dan Bernstein, + Randy Bush, + Steve Crocker, + Olafur Gudmundsson, + Russ Housley, + Rip Loomis, + Allison Mankin, + Paul Mockapetris, + Thomas Narten + Mans Nilsson, + Pekka Savola, + Paul Vixie, + Xunhua Wang, -Atkins & Austein Expires 9 October 2004 [Page 13] +Atkins & Austein Informational [Page 13] -draft-ietf-dnsext-dns-threats-07.txt April 2004 +RFC 3833 DNS Threat Analysis August 2004 - members of the DNS, DNSSEC, DNSIND, and DNSEXT working groups whose - names and contributions the authors have forgotten, none of whom are - responsible for what the authors did with their ideas. + and any other members of the DNS, DNSSEC, DNSIND, and DNSEXT working + groups whose names and contributions the authors have forgotten, none + of whom are responsible for what the authors did with their ideas. As with any work of this nature, the authors of this note acknowledge that we are standing on the toes of those who have gone before us. @@ -739,139 +743,144 @@ draft-ietf-dnsext-dns-threats-07.txt April 2004 Normative References - [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", - RFC 1034, November 1987. + [RFC1034] Mockapetris, P., "Domain names - concepts and + facilities", STD 13, RFC 1034, November 1987. - [RFC1035] Mockapetris, P., "Domain names - implementation and - specification", RFC 1035, November 1987. + [RFC1035] Mockapetris, P., "Domain names - implementation and + specification", STD 13, RFC 1035, November 1987. - [RFC1123] Braden, R., Editor, "Requirements for Internet Hosts - - Application and Support", RFC 1123, October 1989. + [RFC1123] Braden, R., "Requirements for Internet Hosts - + Application and Support", STD 3, RFC 1123, October 1989. - [RFC2181] Elz, R., and R. Bush, "Clarifications to the DNS - Specification" RFC 2181, July 1997. + [RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS + Specification", RFC 2181, July 1997. - [RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS NCACHE)" - RFC 2308, March 1998. + [RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS + NCACHE)", RFC 2308, March 1998. - [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", RFC - 2671, August 1999. + [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", RFC + 2671, August 1999. - [RFC2845] Vixie, P., Gudmundsson, O., Eastlake, D., and B. - Wellington, "Secret Key Transaction Authentication for DNS - (TSIG)" RFC 2845, May 2000. + [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. + Wellington, "Secret Key Transaction Authentication for + DNS (TSIG)", RFC 2845, May 2000. - [RFC2930] Eastlake, D., "Secret Key Establishment for DNS (TKEY RR)" - RFC 2930, September 2000. + [RFC2930] Eastlake 3rd, D., "Secret Key Establishment for DNS + (TKEY RR)", RFC 2930, September 2000. - [RFC3007] Wellington, B., "Secure Domain Name System (DNS) Dynamic - Update" RFC 3007, November 2000. + [RFC3007] Wellington, B., "Secure Domain Name System (DNS) Dynamic + Update", RFC 3007, November 2000. + + [RFC2535] Eastlake 3rd, D., "Domain Name System Security + Extensions", RFC 2535, March 1999. + + + + + + + + + + +Atkins & Austein Informational [Page 14] + +RFC 3833 DNS Threat Analysis August 2004 - [RFC2535] Eastlake, D., "Domain Name System Security Extensions", RFC - 2535, March 1999. Informative References - [RFC3552] Rescorla, E., Korver, B., and the Internet Architecture - Board, "Guidelines for Writing RFC Text on Security - Considerations", RFC 3552, July 2003. - - - - -Atkins & Austein Expires 9 October 2004 [Page 14] - -draft-ietf-dnsext-dns-threats-07.txt April 2004 - + [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC + Text on Security Considerations", BCP 72, RFC 3552, July + 2003. [Bellovin95] Bellovin, S., "Using the Domain Name System for System - Break-Ins", Proceedings of the Fifth Usenix Unix Security - Symposium, June 1995. + Break-Ins", Proceedings of the Fifth Usenix Unix + Security Symposium, June 1995. - [Galvin93] Design team meeting summary message posted to dns- - security@tis.com mailing list by Jim Galvin on 19 November 1993. + [Galvin93] Design team meeting summary message posted to dns- + security@tis.com mailing list by Jim Galvin on 19 + November 1993. - [Schuba93] Schuba, C., "Addressing Weaknesses in the Domain Name - System Protocol", Master's thesis, Purdue University Department - of Computer Sciences, August 1993. + [Schuba93] Schuba, C., "Addressing Weaknesses in the Domain Name + System Protocol", Master's thesis, Purdue University + Department of Computer Sciences, August 1993. - [Vixie95] Vixie, P, "DNS and BIND Security Issues", Proceedings of - the Fifth Usenix Unix Security Symposium, June 1995. + [Vixie95] Vixie, P, "DNS and BIND Security Issues", Proceedings of + the Fifth Usenix Unix Security Symposium, June 1995. -Authors' addresses: +Authors' Addresses - Derek Atkins - IHTFP Consulting, Inc. - 6 Farragut Ave - Somerville, MA 02144 - USA + Derek Atkins + IHTFP Consulting, Inc. + 6 Farragut Ave + Somerville, MA 02144 + USA - Email: derek@ihtfp.com + EMail: derek@ihtfp.com - Rob Austein - Internet Systems Consortium - 950 Charter Street - Redwood City, CA 94063 - USA - Email: sra@isc.org -Intellectual Property Statement + Rob Austein + Internet Systems Consortium + 950 Charter Street + Redwood City, CA 94063 + USA - The IETF takes no position regarding the validity or scope of any - intellectual property or other rights that might be claimed to - pertain to the implementation or use of the technology described in - this document or the extent to which any license under such rights - might or might not be available; neither does it represent that it - has made any effort to identify any such rights. Information on the - IETF's procedures with respect to rights in standards-track and - standards-related documentation can be found in BCP-11. Copies of - claims of rights made available for publication and any assurances of - licenses to be made available, or the result of an attempt made to - obtain a general license or permission for the use of such - proprietary rights by implementors or users of this specification can - be obtained from the IETF Secretariat. - - The IETF invites any interested party to bring to its attention any + EMail: sra@isc.org -Atkins & Austein Expires 9 October 2004 [Page 15] + + + + + + + + + +Atkins & Austein Informational [Page 15] -draft-ietf-dnsext-dns-threats-07.txt April 2004 +RFC 3833 DNS Threat Analysis August 2004 - copyrights, patents or patent applications, or other proprietary - rights which may cover technology that may be required to practice - this standard. Please address the information to the IETF Executive - Director. - Full Copyright Statement - Copyright (C) The Internet Society (2003). All Rights Reserved. + Copyright (C) The Internet Society (2004). This document is subject + to the rights, licenses and restrictions contained in BCP 78, and + except as set forth therein, the authors retain all their rights. - This document and translations of it may be copied and furnished to - others, and derivative works that comment on or otherwise explain it - or assist in its implementation may be prepared, copied, published - and distributed, in whole or in part, without restriction of any - kind, provided that the above copyright notice and this paragraph are - included on all such copies and derivative works. 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Information + on the procedures with respect to rights in RFC documents can be + found in BCP 78 and BCP 79. + + Copies of IPR disclosures made to the IETF Secretariat and any + assurances of licenses to be made available, or the result of an + attempt made to obtain a general license or permission for the use of + such proprietary rights by implementers or users of this + specification can be obtained from the IETF on-line IPR repository at + http://www.ietf.org/ipr. + + The IETF invites any interested party to bring to its attention any + copyrights, patents or patent applications, or other proprietary + rights that may cover technology that may be required to implement + this standard. Please address the information to the IETF at ietf- + ipr@ietf.org. Acknowledgement @@ -886,10 +895,5 @@ Acknowledgement - - - - - -Atkins & Austein Expires 9 October 2004 [Page 16] - +Atkins & Austein Informational [Page 16] +