Bug 29030 - dnsmasq new security issue CVE-2021-3448
Summary: dnsmasq new security issue CVE-2021-3448
Status: RESOLVED FIXED
Alias: None
Product: Mageia
Classification: Unclassified
Component: Security (show other bugs)
Version: 8
Hardware: All Linux
Priority: Normal major
Target Milestone: ---
Assignee: QA Team
QA Contact: Sec team
URL:
Whiteboard: MGA7TOO MGA7-64-OK MGA8-64-OK
Keywords: advisory, validated_update
Depends on:
Blocks:
 
Reported: 2021-05-29 23:12 CEST by David Walser
Modified: 2021-06-08 16:34 CEST (History)
6 users (show)

See Also:
Source RPM: dnsmasq-2.82-2.mga8.src.rpm
CVE: CVE-2021-3448
Status comment:


Attachments

Description David Walser 2021-05-29 23:12:32 CEST
Fedora has issued an advisory on April 23:
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/thread/GHURNEHHUBSW45KMIZ4FNBCSUPWPGV5V/

The issue is fixed upstream in 2.85.

Mageia 7 is also affected.
David Walser 2021-05-29 23:12:45 CEST

Status comment: (none) => Fixed upstream in 2.85
Whiteboard: (none) => MGA7TOO

Comment 1 Julien Moragny 2021-05-30 17:29:18 CEST
Hello,

I just pushed an update to 2.85 for both MGA7 & MGA8 in updates_testing, this version has been released two months ago (and was in cauldron not long after) and no major issue has since surfaced.

Can you please test and (hopefully) validate these updates of dnsmasq. 

You can find a procedure to test the update here (disregard the dnsmasq-base package which doesn't exist anymore): https://bugs.mageia.org/show_bug.cgi?id=19528#c4


Tentatives advisories:

Mageia 8
=======================

Updated dnsmasq packages fix security vulnerability:

CVE-2021-3448: A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.

This kind of configuration is the default when network-manager use dnsmasq.

References:
https://bugs.mageia.org/show_bug.cgi?id=29030
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3448
https://bugzilla.redhat.com/show_bug.cgi?id=1939368

Updated packages in core/updates_testing:
========================
dnsmasq-2.85-1.mga8
dnsmasq-utils-2.85-1.mga8

from dnsmasq-2.85-1.mga8.src.rpm

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


Mageia 7
=======================

Updated dnsmasq packages fix security vulnerability:

CVE-2021-3448: A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.

This kind of configuration is the default when network-manager use dnsmasq.

References:
https://bugs.mageia.org/show_bug.cgi?id=29030
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3448
https://bugzilla.redhat.com/show_bug.cgi?id=1939368

Updated packages in core/updates_testing:
========================
dnsmasq-2.85-1.mga7
dnsmasq-utils-2.85-1.mga7

from dnsmasq-2.85-1.mga7.src.rpm

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

CC: (none) => julien.moragny
Assignee: julien.moragny => qa-bugs
Status: NEW => ASSIGNED

Comment 2 Len Lawrence 2021-05-30 19:31:31 CEST
mga8, x86

# dnsmasq --test
dnsmasq: syntax check OK.
# systemctl enable dnsmasq
# systemctl start dnsmasq
....

Updated the two pckages.
$ rpm -q dnsmasq
dnsmasq-2.85-1.mga8
Referring to earlier test bug 19258#c4 :
# systemctl restart dnsmasq
# dnsmasq --test
dnsmasq: syntax check OK.
# journalctl | grep dnsmasq
....
May 30 17:46:50 canopus systemd[1]: dnsmasq.service: Succeeded.
May 30 17:46:50 canopus dnsmasq[287894]: started, version 2.85 cachesize 150
May 30 17:46:50 canopus dnsmasq[287894]: DNS service limited to local subnets
May 30 17:46:50 canopus dnsmasq[287894]: compile time options: IPv6 GNU-getopt DBus no-UBus i18n IDN2 DHCP DHCPv6 no-Lua TFTP conntrack ipset auth cryptohash DNSSEC loop-detect inotify dumpfile
May 30 17:46:50 canopus dnsmasq[287894]: reading /etc/resolv.conf
May 30 17:46:50 canopus dnsmasq[287894]: using nameserver 192.168.1.1#53
May 30 17:46:50 canopus dnsmasq[287894]: read /etc/hosts - 15 addresses

# netstat -atun
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:53              0.0.0.0:*               LISTEN
udp        0      0 0.0.0.0:53              0.0.0.0:*
udp6       0      0 :::53                   :::*

# host mageia.org 127.0.0.1
Using domain server:
Name: 127.0.0.1
Address: 127.0.0.1#53
Aliases: 

mageia.org has address 163.172.148.228
mageia.org has IPv6 address 2001:bc8:628:1f00::1
mageia.org mail is handled by 10 sucuk.mageia.org.
mageia.org mail is handled by 20 neru.mageia.org.

Following Brian Rockwell:
# dig mageia.org @localhost
;; ANSWER SECTION:
mageia.org.		1604	IN	A	163.172.148.228

$ urpmq -i dnsmasq-utils
......
Name        : dnsmasq-utils                                                    
Version     : 2.83
[...]
Summary     : Utilities for manipulating DHCP server leases
Description :
Utilities that use the standard DHCP protocol to
query/remove a DHCP server's leases.

Could not find anything other than dnsmasq in /sbin.  dnsmasq has a multitude of options and it may be that dnsmasq-utils provides support for those.

Anyway it looks good so far.

Whiteboard: MGA7TOO => MGA7TOO MGA8-64-OK
CC: (none) => tarazed25

Comment 3 Len Lawrence 2021-05-30 21:33:58 CEST
mga7, x64

Updated to latest versions and followed the exact procedures outlined in comment 2 but ran into trouble starting the service.  port 53 was already in use.  Found the pids of the two processes using `ps aux` and deleted both.  OK after that.

dmasq service started successfully and checks returned the same data as in the previous comment.

Giving this an OK for Mageia 7.

Whiteboard: MGA7TOO MGA8-64-OK => MGA7TOO MGA7-64-OK MGA8-64-OK

Comment 4 PC LX 2021-05-31 11:06:31 CEST
Installed and tested without issues.

I use dnsmasq to provide DNS for a LAN and VPN and block unwanted stuff at the DNS level.
dnsmasq's DHCP is not used and thus not tested. Only the DNS part was tested.


System: Mageia 7, x86_64, Intel CPU.



$ uname -a
Linux marte 5.10.41-desktop-1.mga7 #1 SMP Fri May 28 14:28:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
$ rpm -q dnsmasq
dnsmasq-2.85-1.mga7
$ lsof -n | grep IPv.*:domain
dnsmasq   1565                         dnsmasq    4u     IPv4              22465      0t0        UDP *:domain 
dnsmasq   1565                         dnsmasq    5u     IPv4              22466      0t0        TCP *:domain (LISTEN)
dnsmasq   1565                         dnsmasq    6u     IPv6              22467      0t0        UDP *:domain 
dnsmasq   1565                         dnsmasq    7u     IPv6              22468      0t0        TCP *:domain (LISTEN)
$ systemctl status dnsmasq.service 
● dnsmasq.service - DNS caching server.
   Loaded: loaded (/usr/lib/systemd/system/dnsmasq.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2021-05-31 09:44:29 WEST; 17min ago
 Main PID: 1565 (dnsmasq)
    Tasks: 1 (limit: 4668)
   Memory: 1.5M
   CGroup: /system.slice/dnsmasq.service
           └─1565 /usr/sbin/dnsmasq -k --local-service

mai 31 09:44:29 marte systemd[1]: Started DNS caching server..
mai 31 09:44:29 marte dnsmasq[1565]: started, version 2.85 cachesize 150
mai 31 09:44:29 marte dnsmasq[1565]: compile time options: IPv6 GNU-getopt DBus no-UBus i18n IDN2 DHCP DHCPv6 no-Lua TFTP conntrack ipset auth cryptohash DNSSEC loop-detect inotify dumpfile
mai 31 09:44:29 marte dnsmasq[1565]: using nameserver 192.168.1.1#53
mai 31 09:44:29 marte dnsmasq[1565]: read /etc/hosts - 19 addresses

CC: (none) => mageia

Comment 5 Thomas Andrews 2021-05-31 14:05:33 CEST
Validating. Advisories in Comment 1.

Keywords: (none) => validated_update
CC: (none) => andrewsfarm, sysadmin-bugs

Aurelien Oudelet 2021-06-07 08:39:20 CEST

CC: (none) => ouaurelien
Status comment: Fixed upstream in 2.85 => (none)
CVE: (none) => CVE-2021-3448
Keywords: (none) => advisory

Comment 6 Mageia Robot 2021-06-08 16:34:41 CEST
An update for this issue has been pushed to the Mageia Updates repository.

https://advisories.mageia.org/MGASA-2021-0231.html

Status: ASSIGNED => RESOLVED
Resolution: (none) => FIXED


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