AIX is vulnerable to denial of service due to ISC BIND

IBM SECURITY ADVISORY

First Issued: Tue Jun 4 16:06:25 CDT 2024
|Updated: Wed Jun 5 08:17:08 CDT 2024
|Update: Corrected the affected fileset levels to reflect that
| bind.rte 7.1.916.2604 and 7.3.916.2601 are vulnerable.

The most recent version of this document is available here:
https://aix.software.ibm.com/aix/efixes/security/bind_advisory26.asc

Security Bulletin: AIX is vulnerable to denial of service due to ISC BIND

===============================================================================

SUMMARY:

Multiple vulnerabilities in ISC BIND could allow a remote attacker to
cause a denial of service. AIX uses ISC BIND as part of its DNS functions.

===============================================================================

VULNERABILITY DETAILS:

CVEID: CVE-2023-50868
    https://vulners.com/cve/CVE-2023-50868
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an
    error when preparing an NSEC3 closest encloser proof. By flooding the
    target resolver with queries, a remote attacker could exploit this
    vulnerability to cause CPU exhaustion on a DNSSEC-validating resolver.
CVSS Base Score: 7.5
CVSS Temporal Score: See 
    https://exchange.xforce.ibmcloud.com/vulnerabilities/282901
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID: CVE-2023-50387
    https://vulners.com/cve/CVE-2023-50387
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an
    error when processing responses coming from specially crafted
    DNSSEC-signed zones. By flooding the target server with queries, a
    remote attacker could exploit this vulnerability to cause CPU
    exhaustion on a DNSSEC-validating resolver.
CVSS Base Score: 7.5
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/281081
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID: CVE-2023-4408
    https://vulners.com/cve/CVE-2023-4408
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an
    error when parsing large DNS messages. By flooding the target server
    with queries, a remote attacker could exploit this vulnerability to
    cause excessive CPU load.
CVSS Base Score: 7.5
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/282906
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID: CVE-2023-6516
    https://vulners.com/cve/CVE-2023-6516
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an
    out-of-memory condition. By using specific recursive query patterns, a
    remote attacker could exploit this vulnerability to cause the amount of
    memory used by a named resolver to go well beyond the configured
    max-cache-size limit, leading to a denial of service.
CVSS Base Score: 7.5
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/282902
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID: CVE-2023-5679
    https://vulners.com/cve/CVE-2023-5679
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an
    error when enabling both DNS64 and serve-stale. By querying a
    DNS64-enabled resolver for domain names triggering serve-stale, a
    remote attacker could exploit this vulnerability to trigger an
    assertion failure.
CVSS Base Score: 7.5
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/282904
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID: CVE-2023-5517
    https://vulners.com/cve/CVE-2023-5517
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by a
    flaw in query-handling code. By querying RFC 1918 reverse zones, a
    remote attacker could exploit this vulnerability to trigger an
    assertion failure.
CVSS Base Score: 7.5
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/282905
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)


AFFECTED PRODUCTS AND VERSIONS:

    AIX 7.2, 7.3
    VIOS 3.1, 4.1

    The following fileset levels are vulnerable:
    
    key_fileset = aix

    Fileset                 Lower Level  Upper Level  KEY
    ----------------------------------------------------------
    bind.rte                7.1.916.0    7.1.916.2604 key_w_fs
    bind.rte                7.2.916.0    7.2.916.2600 key_w_fs
    bind.rte                7.3.916.0    7.3.916.2601 key_w_fs
    
    To find out whether the affected filesets are installed 
    on your systems, refer to the lslpp command found in AIX user's guide.

    Example:  lslpp -L | grep -i bind.rte


REMEDIATION:

    A. FIXES

        IBM strongly recommends addressing the vulnerability now.

        The AIX and VIOS fixes can be downloaded via https from:

        https://aix.software.ibm.com/aix/efixes/security/bind_fix26.tar 

        The link above is to a tar file containing this signed
        advisory, install packages, and OpenSSL signatures for each
        package. The fixes below include prerequisite checking. This will
        enforce the correct mapping between the fixes and AIX
        Technology Levels.

        To extract the fixes from the tar file:

        tar xvf bind_fix26.tar

        For AIX 7.2 and VIOS 3.1 with OpenSSL 1.0 installed:
        tar xvf bind_fix26/71bind916.tar

        For AIX 7.2 and VIOS 3.1 with OpenSSL 1.1 installed:
        tar xvf bind_fix26/72bind916.tar

        For AIX 7.3 and VIOS 4.1:
        tar xvf bind_fix26/73bind916.tar

        IMPORTANT: If possible, it is recommended that a mksysb backup
        of the system be created. Verify it is both bootable and
        readable before proceeding.

        To preview the fix installation:

        installp -apYd . bind 

        To install the fix package:

        installp -aXYd . bind

        Verify you have retrieved the fixes intact:

        The checksums below were generated using the
        "openssl dgst -sha256 [file]" command as the following:

        openssl dgst -sha256                                              filename   KEY
        ---------------------------------------------------------------------------------------
        1a44cbf3ada06c29efdaad7757ab248995e0623689a5ca8682e4c610cd127364  71bind.rte key_w_csum
        4016a2ffafda43b8deb9039dd6736a1b9bf3eb11afba0889041ae2e00dec5237  72bind.rte key_w_csum
        4ed621e5f8957739023e370e04ef58bf38ee96489c6ba0f54181b40bcf239b8c  73bind.rte key_w_csum


        These sums should match exactly. The OpenSSL signatures in the tar
        file and on this advisory can also be used to verify the
        integrity of the fixes.  If the sums or signatures cannot be
        confirmed, contact IBM Support at
        http://ibm.com/support/ and describe the discrepancy.         

        openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file]

        openssl dgst -sha256 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file]

        Published advisory OpenSSL signature file location:

        https://aix.software.ibm.com/aix/efixes/security/bind_advisory26.asc.sig

    C. FIX AND INTERIM FIX INSTALLATION

        If possible, it is recommended that a mksysb backup of the system 
        be created. Verify it is both bootable and readable before
        proceeding.

        To preview a fix installation:

        installp -a -d fix_name -p all  # where fix_name is the name of the
                                        # fix package being previewed.
        To install a fix package:

        installp -a -d fix_name -X all  # where fix_name is the name of the
                                        # fix package being installed.

        Interim fixes have had limited functional and regression
        testing but not the full regression testing that takes place
        for Service Packs; however, IBM does fully support them.

        Interim fix management documentation can be found at:

        https://www.ibm.com/support/pages/managing-interim-fixes-aix

        To preview an interim fix installation:

        emgr -e ipkg_name -p         # where ipkg_name is the name of the
                                     # interim fix package being previewed.

        To install an interim fix package:

        emgr -e ipkg_name -X         # where ipkg_name is the name of the
                                     # interim fix package being installed.

WORKAROUNDS AND MITIGATIONS:

    None.

===============================================================================

CONTACT US:

Note: Keywords labeled as KEY in this document are used for parsing
purposes.

If you would like to receive AIX Security Advisories via email,
please visit "My Notifications":

    https://www.ibm.com/support/mynotifications

Contact IBM Support for questions related to this announcement:

    https://ibm.com/support/

For information on how to securely verify AIX security bulletins and fixes:

    https://www.ibm.com/support/pages/node/6985269

To obtain the OpenSSL public key that can be used to verify the
signed advisories and ifixes:

    Download the key from our web page:

https://aix.software.ibm.com/aix/efixes/security/systems_p_os_aix_security_pubkey.txt

To verify the AIX/VIOS security bulletin:

    Published advisory OpenSSL signature file location:

    https://aix.software.ibm.com/aix/efixes/security/bind_advisory26.asc.sig

    openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file]

Please contact your local IBM AIX support center for any
assistance.

REFERENCES:

Complete CVSS v3 Guide: http://www.first.org/cvss/user-guide
On-line Calculator v3:
    http://www.first.org/cvss/calculator/3.0

RELATED INFORMATION:

IBM Secure Engineering Web Portal
    http://www.ibm.com/security/secure-engineering/bulletins.html

IBM Product Security Incident Response Blog
    https://www.ibm.com/blogs/psirt/

Security Bulletin: AIX is vulnerable to denial of service due to ISC BIND
    https://www.ibm.com/support/pages/node/7156443

ACKNOWLEDGEMENTS:

None.

CHANGE HISTORY:

First Issued: Tue Jun  4 16:06:25 CDT 2024

| Updated: Wed Jun 5 08:17:08 CDT 2024
| Update: Corrected the affected fileset levels to reflect that
| bind.rte 7.1.916.2604 and 7.3.916.2601 are vulnerable.

===============================================================================

*The CVSS Environment Score is customer environment specific and will
ultimately impact the Overall CVSS Score. Customers can evaluate the impact
of this vulnerability in their environments by accessing the links in the
Reference section of this Security Bulletin.

Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the
Common Vulnerability Scoring System (CVSS) is an “industry open standard
designed to convey vulnerability severity and help to determine urgency and
priority of response.” IBM PROVIDES THE CVSS SCORES “AS IS” WITHOUT WARRANTY
OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT
OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.