Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.1834.2 USN-4969-1: DHCP vulnerability 8 June 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: isc-dhcp Publisher: Ubuntu Operating System: Ubuntu UNIX variants (UNIX, Linux, OSX) Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2021-25217 Original Bulletin: https://ubuntu.com/security/notices/USN-4969-1 https://ubuntu.com/security/notices/USN-4969-2 https://ubuntu.com/security/notices/USN-4969-3 Comment: This bulletin contains three (3) Ubuntu security advisories. Revision History: June 8 2021: Regression fix detailed in USN-4969-3 May 28 2021: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- USN-4969-1: DHCP vulnerability 27 May 2021 DHCP could be made to crash if it received specially crafted network traffic. Releases o Ubuntu 21.04 o Ubuntu 20.10 o Ubuntu 20.04 LTS o Ubuntu 18.04 LTS Packages o isc-dhcp - DHCP server and client Details Jon Franklin and Pawel Wieczorkiewicz discovered that DHCP incorrectly handled lease file parsing. A remote attacker could possibly use this issue to cause DHCP to crash, resulting in a denial of service. Update instructions The problem can be corrected by updating your system to the following package versions: Ubuntu 21.04 o isc-dhcp-server - 4.4.1-2.2ubuntu6.1 o isc-dhcp-client - 4.4.1-2.2ubuntu6.1 Ubuntu 20.10 o isc-dhcp-server - 4.4.1-2.1ubuntu10.1 o isc-dhcp-client - 4.4.1-2.1ubuntu10.1 Ubuntu 20.04 o isc-dhcp-server - 4.4.1-2.1ubuntu5.20.04.2 o isc-dhcp-client - 4.4.1-2.1ubuntu5.20.04.2 Ubuntu 18.04 o isc-dhcp-server - 4.3.5-3ubuntu7.3 o isc-dhcp-client - 4.3.5-3ubuntu7.3 In general, a standard system update will make all the necessary changes. References o CVE-2021-25217 Related notices o USN-4969-2 : isc-dhcp-client, isc-dhcp-server, isc-dhcp - ------------------------------------------------------------------------------ USN-4969-2: DHCP vulnerability 27 May 2021 DHCP could be made to crash if it received specially crafted network traffic. Releases o Ubuntu 16.04 ESM o Ubuntu 14.04 ESM Packages o isc-dhcp - DHCP server and client Details USN-4969-1 fixed a vulnerability in DHCP. This update provides the corresponding update for Ubuntu 14.04 ESM and 16.04 ESM. Original advisory details: Jon Franklin and Pawel Wieczorkiewicz discovered that DHCP incorrectly handled lease file parsing. A remote attacker could possibly use this issue to cause DHCP to crash, resulting in a denial of service. Update instructions The problem can be corrected by updating your system to the following package versions: Ubuntu 16.04 o isc-dhcp-server - 4.3.3-5ubuntu12.10+esm1 Available with UA Infra or UA Desktop o isc-dhcp-client - 4.3.3-5ubuntu12.10+esm1 Available with UA Infra or UA Desktop Ubuntu 14.04 o isc-dhcp-server - 4.2.4-7ubuntu12.13+esm1 Available with UA Infra or UA Desktop o isc-dhcp-client - 4.2.4-7ubuntu12.13+esm1 Available with UA Infra or UA Desktop In general, a standard system update will make all the necessary changes. References o CVE-2021-25217 Related notices o USN-4969-1 : isc-dhcp-client, isc-dhcp, isc-dhcp-server - ------------------------------------------------------------------------------ USN-4969-3: DHCP regression 07 June 2021 USN-4969-1 introduced a regression in DHCP. Releases o Ubuntu 21.04 Packages o isc-dhcp - DHCP server and client Details USN-4969-1 fixed a vulnerability in DHCP. The package for Ubuntu 21.04 introduced a regression causing it to reject certain valid configuration files. This update fixes the problem. We apologize for the inconvenience. Original advisory details: Jon Franklin and Pawel Wieczorkiewicz discovered that DHCP incorrectly handled lease file parsing. A remote attacker could possibly use this issue to cause DHCP to crash, resulting in a denial of service. Update instructions The problem can be corrected by updating your system to the following package versions: Ubuntu 21.04 o isc-dhcp-client - 4.4.1-2.2ubuntu6.2 o isc-dhcp-server - 4.4.1-2.2ubuntu6.2 In general, a standard system update will make all the necessary changes. References o https://launchpad.net/bugs/1930917 - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBYL7K8uNLKJtyKPYoAQhkAQ/8DMcv+f4dTkU1U4cOdMHTxdLoU1QFsVn/ u6QYiaRflpCz8AkDQa2Y4uJm0tJ3xW0grN198U5zj7ttM+nY+iyZwuwGIEqocgBc oCloY4Ow7cNpgh6MWJhP3838ktLsiwrEc33jpZjkn1Ey/demE+yOfwNjBPTGcsx1 tKumbn5R5Jyadmif+JPeNTUlQcXvmCGNb+X1ANBh2Fn+FHYIUOZaadpB53pUEDDk HTdfsRroKudM0MjOJWS8qAHqQ3VBenhYVD5IjZRQgf7zwBGdefpCFNuWrsW4ug/A rL3zEzjMSXDhjR9iFd0/vdOo4INJGvzPVIYyvB22DzI9kJzFSOZQpDyq8C+FTtVk 0oAQtzE3lQFWn6vOljBC8pxqVMVA5mmN50lb57WWnWqMhMmwrRr4BkufQg8Vi/+i QKdzfa25FbLHPgsyKO1ko8130dpR59DoEAnEWuJ0duu7E7k7U324GRWCEOBof6RF qYY6jvxGHMBmyq4jx6V4R1st2bZVjHo6suPc+//ZZozNfpIA3JvpsGmbXVsBkzFQ Xx4buFu0O/g6Nlf8UweF289Y9xDiloz3Cpeb7dudEsFMSavKrLqVGMaxA97hrolp u4TOZa9RguafHlbX9gqVe8aLIZATtmzfn4BX+a6pH+fsclyzHkpBZSvhL95oOPBH xvehtKkU9qA= =L1hJ -----END PGP SIGNATURE-----