AIX is vulnerable to arbitrary command execution due to Perl (CVE-2024-25021 CVE-2023-47038 CVE-2023-47100)

IBM SECURITY ADVISORY

First Issued: Wed Feb 21 15:59:59 CST 2024

The most recent version of this document is available here:
https://aix.software.ibm.com/aix/efixes/security/perl_advisory8.asc

Security Bulletin: AIX is vulnerable to arbitrary command execution due to
Perl (CVE-2024-25021, CVE-2023-47038, CVE-2023-47100)

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

SUMMARY:

Vulnerabilities in AIX's Perl could allow an attacker to execute arbitrary
commands (CVE-2024-25021, CVE-2023-47038, CVE-2023-47100) AIX uses Perl in
various operating system components.

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

VULNERABILITY DETAILS:

CVEID: CVE-2024-25021
    https://vulners.com/cve/CVE-2024-25021
DESCRIPTION: IBM AIX's Perl implementation could allow a non-privileged
    local user to exploit a vulnerability to execute arbitrary commands.
CVSS Base Score: 8.4
CVSS Temporal Score: See 
    https://exchange.xforce.ibmcloud.com/vulnerabilities/281320
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

CVEID: CVE-2023-47038
    https://vulners.com/cve/CVE-2023-47038
DESCRIPTION: Perl is vulnerable to a heap-based buffer overflow, caused by
    improper bounds checking by the user-defined Unicode property. By
    persuading a victim to use specially crafted regular expression to
    compile, a remote attacker could overflow a buffer and execute
    arbitrary code on the system.
CVSS Base Score: 7.8
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/272814
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)

CVEID: CVE-2023-47100
    https://vulners.com/cve/CVE-2023-47100
DESCRIPTION: Perl could allow a remote attacker to bypass security
    restrictions, caused by improper handling of property name by the
    S_parse_uniprop_string function in regcomp.c. By using a specially
    crafted regular expression input, an attacker could exploit this
    vulnerability to write to unallocated space.
CVSS Base Score: 9.8
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/272992
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)


AFFECTED PRODUCTS AND VERSIONS:

    AIX 7.3
    VIOS 4.1

    The following fileset levels are vulnerable:
    
    key_fileset = aix

    Fileset                 Lower Level  Upper Level KEY 
    ---------------------------------------------------------
    perl.rte                5.34.0.0     5.34.1.5    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 perl.rte


REMEDIATION:

    A. FIXES

        IBM strongly recommends addressing the vulnerability now.

        AIX and VIOS fileset updates are available.

        The AIX and VIOS fileset update can be downloaded via https from,
        under 'Perl - Perl Version 5 Runtime':

        https://www.ibm.com/resources/mrs/assets?source=aixbp

        For AIX 7.3 TL1 and above, and for VIOS 4.1:
        perl.rte.5.34.1.6

        The fileset update has a dependency on OpenSSL 3.0.

        Alternatively, AIX and VIOS fixes are also available.

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

        https://aix.software.ibm.com/aix/efixes/security/perl_fix8.tar

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

        AIX Level      Interim Fix (*.Z)        Fileset Name(prereq for installation) KEY
        ---------------------------------------------------------------------------------------
        7.3.1, 7.3.2   perl5345ma.240213.epkg.Z perl.rte(5.34.1.2)                    key_w_fix

        VIOS Level     Interim Fix (*.Z)        Fileset Name(prereq for installation) KEY
        ---------------------------------------------------------------------------------------
        4.1            perl5345ma.240213.epkg.Z perl.rte(5.34.1.2)                    key_w_fix 

        To extract the fixes from the tar file:

        tar xvf perl_fix8.tar
        cd perl_fix8

        Verify you have retrieved the fixes intact:

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

        openssl dgst -sha256                                              filename                 KEY
        -----------------------------------------------------------------------------------------------------
        3429696297740123a42cd1957c54caa8a72e398252e063836579adc29863e031  perl5345ma.240213.epkg.Z 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/perl_advisory8.asc.sig

    B. 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 the fileset installation:

        installp -apYd . perl

        To install the fileset update:

        installp -aXYd . perl

        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":

    http://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/perl_advisory8.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 arbitrary command execution due
    to Perl (CVE-2024-25021, CVE-2023-47038, CVE-2023-47100) 
    https://www.ibm.com/support/pages/node/7122628

ACKNOWLEDGEMENTS:

None.

CHANGE HISTORY:

First Issued: Wed Feb 21 15:59:59 CST 2024

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

*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.