A malicious actor who intentionally exploits this lack of effective limitation on the number of fetches performed when processing referrals can, through the use of specially crafted referrals, cause a recursing server to issue a very large number of fetches in an attempt to process the referral. This has at least two potential effects: The performance of the recursing server can potentially be degraded by the additional work required to perform these fetches, and The attacker can exploit this behavior to use the recursing server as a reflector in a reflection attack with a high amplification factor.
Metrics
CVSS Version: 3.1 |
Base Score: 8.6 HIGH Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CWE-ID: CWE Name: In order for a server performing recursion to locate records in the DNS graph it must be capable of processing referrals, such as those received when it attempts to query an authoritative server for a record which is delegated elsewhere. In its original design BIND (as well as other nameservers) does not sufficiently limit the number of fetches which may be performed while processing a referral response. BIND 9.0.0 -> 9.11.18, 9.12.0 -> 9.12.4-P2, 9.14.0 -> 9.14.11, 9.16.0 -> 9.16.2, and releases 9.17.0 -> 9.17.1 of the 9.17 experimental development branch. All releases in the obsolete 9.13 and 9.15 development branches. All releases of BIND Supported Preview Edition from 9.9.3-S1 -> 9.11.18-S1. Source: ISC
Common Attack Pattern Enumeration and Classification (CAPEC)