IBM SECURITY ADVISORY First Issued: Fri Sep 23 09:39:22 CDT 2022 The most recent version of this document is available here: http://aix.software.ibm.com/aix/efixes/security/rpm_advisory.asc https://aix.software.ibm.com/aix/efixes/security/rpm_advisory.asc ftp://aix.software.ibm.com/aix/efixes/security/rpm_advisory.asc Security Bulletin: Due to RPM, AIX is vulnerable to arbitrary code execution (CVE-2021-20271), RPM database corruption (CVE-2021-3421), and denial of service (CVE-2021-20266) =============================================================================== SUMMARY: AIX is vulnerable to arbitrary code execution (CVE-2021-20271), RPM database corruption (CVE-2021-3421), and denial of service (CVE-2021-20266) due to RPM. RPM is used by AIX for package management. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2021-20271 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-20271 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-20271 DESCRIPTION: RPM could allow a remote attacker to execute arbitrary code on the system, caused by a flaw in the signature check function. By persuading a victim to open a specially-crafted package file, an attacker could exploit this vulnerability to cause RPM database corruption and execute arbitrary code on the system. CVSS Base Score: 6.7 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/198961 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H) CVEID: CVE-2021-3421 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3421 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3421 DESCRIPTION: RPM Project RPM could allow a remote attacker to bypass security restrictions, caused by a flaw in the read function. By persuading a victim to install a seemingly verifiable package or compromise an RPM repository, an attacker could exploit this vulnerability to cause a corruption to the RPM database. CVSS Base Score: 6.1 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/203124 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L) CVEID: CVE-2021-20266 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-20266 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-20266 DESCRIPTION: RPM Project RPM is vulnerable to a denial of service, caused by an out-of-bounds read flaw in the hdrblobInit function in lib/header.c. By sending a specially-crafted request, a local authenticated attacker could exploit this vulnerability to cause a denial of service condition. CVSS Base Score: 3.1 CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/201041 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L) AFFECTED PRODUCTS AND VERSIONS: AIX 7.1, 7.2, 7.3 VIOS 3.1 The following fileset levels are vulnerable: key_fileset = aix Fileset Lower Level Upper Level KEY --------------------------------------------------------- rpm.rte 4.9.1.3 4.15.1.1005 key_w_fs rpm.rte 4.15.1.2000 4.15.1.2005 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 rpm.rte REMEDIATION: A. FIXES IBM strongly recommends addressing the vulnerability now. AIX and VIOS fixes are available. The AIX and VIOS fixes can be downloaded via ftp or http from: ftp://aix.software.ibm.com/aix/efixes/security/rpm_fix.tar http://aix.software.ibm.com/aix/efixes/security/rpm_fix.tar https://aix.software.ibm.com/aix/efixes/security/rpm_fix.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 AIX Technology Levels. AIX Level Fix KEY --------------------------------------------------- 7.1, 7.2 rpm.rte.4.15.1.1006 key_w_fix 7.3 rpm.rte.4.15.1.2006 key_w_fix VIOS Level Fix KEY --------------------------------------------------- 3.1 rpm.rte.4.15.1.1006 key_w_fix To extract the fixes from the tar file: tar xvf rpm_fix.tar cd rpm_fix 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 ------------------------------------------------------------------------------------------------ f12ab2fa1cce9129dc27f2d8a6af1f3e5a1075c93da87ff5f67519d19cfd8db1 rpm.rte.4.15.1.1006 key_w_csum 942c99ecb388645676e3f9361b0157406997188f4249ff7d07ee58bf3271cc34 rpm.rte.4.15.1.2006 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: http://aix.software.ibm.com/aix/efixes/security/rpm_advisory.asc.sig https://aix.software.ibm.com/aix/efixes/security/rpm_advisory.asc.sig ftp://aix.software.ibm.com/aix/efixes/security/rpm_advisory.asc.sig B. 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 fix installation: For AIX 7.1 and 7.2: installp -apYd . rpm.rte 4.15.1.1006 For AIX 7.3: installp -apYd . rpm.rte 4.15.1.2006 To install the fix package: For AIX 7.1 and 7.2: installp -aXYd . rpm.rte 4.15.1.1006 For AIX 7.3: installp -aXYd . rpm.rte 4.15.1.2006 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 To view previously issued advisories, please visit: http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq Contact IBM Support for questions related to this announcement: http://ibm.com/support/ https://ibm.com/support/ To obtain the OpenSSL public key that can be used to verify the signed advisories and ifixes: Download the key from our web page: ftp://ftp.software.ibm.com/systems/power/AIX/systems_p_os_aix_security_pubkey.txt 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: Due to RPM, AIX is vulnerable to arbitrary code execution (CVE-2021-20271), RPM database corruption (CVE-2021-3421), and denial of service (CVE-2021-20266) https://www.ibm.com/support/pages/node/6823145 ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Fri Sep 23 09:39:22 CDT 2022 =============================================================================== *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.