Bug #7436: bind: An error processing RPZ rules can cause named to loop endlessly after handling a query (CVE-2017-3140)
[3.6] bind: An error processing RPZ rules can cause named to loop endlessly after handling a query (CVE-2017-3140)
If named is configured to use Response Policy Zones (RPZ) an error processing some rule types can lead to
a condition where BIND will endlessly loop while handling a query.
A server is potentially vulnerable to degradation of service if
1. the server is configured to use RPZ,
2. the server uses NSDNAME or NSIP policy rules, and
3. an attacker can cause the server to process a specific query
Successful exploitation of this condition will cause named to enter a state where it continues to loop while processing the query without ever reaching an end state.
While in this state, named repeatedly queries the same sets of authoritative nameservers and this behavior will usually persist indefinitely beyond the normal client
query processing timeout. By triggering this condition multiple times, an attacker could cause a deliberate and substantial degradation in service.
Operators of servers that meet the above conditions 1. and 2. may also accidentally encounter this defect during normal operation. It is for this reason that the decision
was made to issue this advisory despite its low CVSS score.
9.9.10, 9.10.5, 9.11.0->9.11.1, 9.9.10-S1, 9.10.5-S1
BIND 9 version 9.11.1-P1