Security Bulletin
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
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 Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
CVEID: 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 Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
CVEID: 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 Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| AIX | 7.3 |
| VIOS | 4.1 |
The following fileset levels are vulnerable:
| Fileset | Lower Level | Upper Level |
| perl.rte | 5.34.0.0 | 5.34.1.5 |
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/Fixes
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 | Fileset Name(prereq for installation) |
| 7.3.1, 7.3.2 | perl5345ma.240213.epkg.Z | perl.rte(5.34.1.2) |
| VIOS Level | Interim Fix | Fileset Name(prereq for installation) |
| 4.1 | perl5345ma.240213.epkg.Z | perl.rte(5.34.1.2) |
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 |
| 3429696297740123a42cd1957c54caa8a72e398252e063836579adc29863e031 | perl5345ma.240213.epkg.Z |
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
Get Notified about Future Security Bulletins
References
Acknowledgement
The vulnerability for CVE-2024-25021 was reported to IBM by Paul M. Gunsch.
Change History
21 Feb 2024: Initial Publication
*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. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
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Document Information
Modified date:
23 February 2024
UID
ibm17122628