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From 410a6ce5c80dd981c22752da034f2529b5eee844 Mon Sep 17 00:00:00 2001
From: sebres <serg.brester@sebres.de>
Date: Mon, 21 Jun 2021 17:12:53 +0200
Subject: [PATCH] fixed possible RCE vulnerability, unset escape variable
(default tilde) stops consider "~" char after new-line as composing escape
sequence
---
config/action.d/complain.conf | 2 +-
config/action.d/dshield.conf | 2 +-
config/action.d/mail-buffered.conf | 8 ++++----
config/action.d/mail-whois-lines.conf | 2 +-
config/action.d/mail-whois.conf | 6 +++---
config/action.d/mail.conf | 6 +++---
6 files changed, 13 insertions(+), 13 deletions(-)
--- a/config/action.d/complain.conf
+++ b/config/action.d/complain.conf
@@ -102,7 +102,7 @@ logpath = /dev/null
# Notes.: Your system mail command. Is passed 2 args: subject and recipient
# Values: CMD
#
-mailcmd = mail -s
+mailcmd = mail -E 'set escape' -s
# Option: mailargs
# Notes.: Additional arguments to mail command. e.g. for standard Unix mail:
--- a/config/action.d/dshield.conf
+++ b/config/action.d/dshield.conf
@@ -179,7 +179,7 @@ tcpflags =
# Notes.: Your system mail command. Is passed 2 args: subject and recipient
# Values: CMD
#
-mailcmd = mail -s
+mailcmd = mail -E 'set escape' -s
# Option: mailargs
# Notes.: Additional arguments to mail command. e.g. for standard Unix mail:
--- a/config/action.d/mail-buffered.conf
+++ b/config/action.d/mail-buffered.conf
@@ -17,7 +17,7 @@ actionstart = printf %%b "Hi,\n
The jail <name> has been started successfully.\n
Output will be buffered until <lines> lines are available.\n
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
# Option: actionstop
# Notes.: command executed at the stop of jail (or at the end of Fail2Ban)
@@ -28,13 +28,13 @@ actionstop = if [ -f <tmpfile> ]; then
These hosts have been banned by Fail2Ban.\n
`cat <tmpfile>`
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: Summary from <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: Summary from <fq-hostname>" <dest>
rm <tmpfile>
fi
printf %%b "Hi,\n
The jail <name> has been stopped.\n
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
# Option: actioncheck
# Notes.: command executed once before each actionban command
@@ -55,7 +55,7 @@ actionban = printf %%b "`date`: <ip> (<f
These hosts have been banned by Fail2Ban.\n
`cat <tmpfile>`
\nRegards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: Summary" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: Summary" <dest>
rm <tmpfile>
fi
--- a/config/action.d/mail-whois-lines.conf
+++ b/config/action.d/mail-whois-lines.conf
@@ -72,7 +72,7 @@ actionunban =
# Notes.: Your system mail command. Is passed 2 args: subject and recipient
# Values: CMD
#
-mailcmd = mail -s
+mailcmd = mail -E 'set escape' -s
# Default name of the chain
#
--- a/config/action.d/mail-whois.conf
+++ b/config/action.d/mail-whois.conf
@@ -20,7 +20,7 @@ norestored = 1
actionstart = printf %%b "Hi,\n
The jail <name> has been started successfully.\n
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
# Option: actionstop
# Notes.: command executed at the stop of jail (or at the end of Fail2Ban)
@@ -29,7 +29,7 @@ actionstart = printf %%b "Hi,\n
actionstop = printf %%b "Hi,\n
The jail <name> has been stopped.\n
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
# Option: actioncheck
# Notes.: command executed once before each actionban command
@@ -49,7 +49,7 @@ actionban = printf %%b "Hi,\n
Here is more information about <ip> :\n
`%(_whois_command)s`\n
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: banned <ip> from <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: banned <ip> from <fq-hostname>" <dest>
# Option: actionunban
# Notes.: command executed when unbanning an IP. Take care that the
--- a/config/action.d/mail.conf
+++ b/config/action.d/mail.conf
@@ -16,7 +16,7 @@ norestored = 1
actionstart = printf %%b "Hi,\n
The jail <name> has been started successfully.\n
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: started on <fq-hostname>" <dest>
# Option: actionstop
# Notes.: command executed at the stop of jail (or at the end of Fail2Ban)
@@ -25,7 +25,7 @@ actionstart = printf %%b "Hi,\n
actionstop = printf %%b "Hi,\n
The jail <name> has been stopped.\n
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: stopped on <fq-hostname>" <dest>
# Option: actioncheck
# Notes.: command executed once before each actionban command
@@ -43,7 +43,7 @@ actionban = printf %%b "Hi,\n
The IP <ip> has just been banned by Fail2Ban after
<failures> attempts against <name>.\n
Regards,\n
- Fail2Ban"|mail -s "[Fail2Ban] <name>: banned <ip> from <fq-hostname>" <dest>
+ Fail2Ban"|mail -E 'set escape' -s "[Fail2Ban] <name>: banned <ip> from <fq-hostname>" <dest>
# Option: actionunban
# Notes.: command executed when unbanning an IP. Take care that the
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