CVE-2017-3135: Combination of DNS64 and RPZ Can Lead to Crash

Brian Conry bconry at
Wed Feb 8 22:36:58 UTC 2017

Some configurations using both DNS64 and RPZ can lead to an INSIST
assertion failure or a NULL pointer read; in either case named will

CVE:               CVE-2017-3135
Document Version:  2.0
Posting date:      08 Feb 2017
Program Impacted:  BIND
Versions affected: 9.9.3-S1 -> 9.9.9-S7, 9.9.3 -> 9.9.9-P5, 9.9.10b1,
                   9.10.0 -> 9.10.4-P5, 9.10.5b1, 9.11.0 -> 9.11.0-P2,
Severity:          High, for servers with specific configurations
Exploitable:       Remotely, but only affecting servers with specific


    Under some conditions when using both DNS64 and RPZ to rewrite query
    responses, query processing can resume in an inconsistent state
    leading to either an INSIST assertion failure or an attempt to read
    through a NULL pointer.


    Servers utilizing both DNS64 and RPZ are potentially susceptible to
    encountering this condition.  When this condition occurs, it will
    result in either an INSIST assertion failure (and subsequent abort)
    or an attempt to read through a NULL pointer.  On most platforms a
    NULL pointer read leads to a segmentation fault (SEGFAULT), which
    causes the process to be terminated.

    Only servers which are configured to simultaneously use both
    Response Policy Zones (RPZ) and DNS64 (a method for synthesizing
    AAAA records from A records) can be affected by this vulnerability.

CVSS Score:  7.5

    For more information on the Common Vulnerability Scoring System and
    to obtain your specific environmental score please visit:


    While it is possible to avoid the condition by removing either DNS64
    or RPZ from the configuration, or by carefully restricting the
    contents of the policy zone, for an affected configuration the most
    practical and safest course of action is to upgrade to a version of
    BIND without this vulnerability.

Active exploits:

    No known active exploits.


    Upgrade to the patched release most closely related to your current
    version of BIND. These can all be downloaded from

        BIND 9 version 9.9.9-P6
        BIND 9 version 9.10.4-P6
        BIND 9 version 9.11.0-P3

    BIND Supported Preview Edition is a special feature preview branch
    of BIND provided to eligible ISC support customers.

        BIND 9 version 9.9.9-S8


    ISC would like to thank Ramesh Damodaran(Infoblox) and Aliaksandr
    Shubnik (Infoblox) for reporting the issue and assisting us in the

Document Revision History:

    1.0 Advance Notification 01 Feb, 2017
    2.0 Public Announcement 08 Feb, 2017

Related Documents:

    See our BIND9 Security Vulnerability Matrix at for a complete listing of
    Security Vulnerabilities and versions affected.

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