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Tuesday, January 31, 2012

Unknown SQL engine

Problem:After installing the FreePBX,admin page show  the following message:

Unknown SQL engine: []
Trace Back
/var/www/html/admin/common/db_connect.php:57 die_freepbx()
[0]: Unknown SQL engine: []
/var/www/html/admin/bootstrap.php:75 require_once()
[0]: /var/www/html/admin/common/db_connect.php
/var/www/html/admin/config.php:61 require()
[0]: /var/www/html/admin/bootstrap.php

Solution:vim +231 /etc/httpd/conf/httpd.confchange User apache and Group apache to User asterisk and Group asterisk.
vim +327 /etc/httpd/conf/httpd.confchange None to All.
or use sed to replace.
sed -i '231,232s/apache/asterisk/i;327s/none/All/i' /etc/httpd/conf/httpd.confRestart apache service.
service httpd restart

[solved] configure: *** XML documentation will not be available because the 'libxml2' development package is missing.

yum install install libxml2-devel
Nguyen Si Nhan

[solved] configure: error: *** termcap support not found (on modern systems, this typically means the ncurses development package is missing),

# yum install ncurses-devel
Nguyen Si Nhan 

[solved] error: C++ preprocessor /lib/cpp fails sanity check

you just run this cmd:
# yum install gcc-c++
Nguyen Si Nhan

Monday, January 30, 2012

[solved] You do not appear to have the sources for the 2.6.18-274.17.1.el5 kernel installed.

When installing asterisk and the zaptel or dahdi module, you may reach the error:
You do not appear to have the sources for <your-kernel-version>
Here, I will explain exactly what asterisk is looking for and how you can fix it.
First, you may really need to install the kernel sources. The headers are needed to compile zaptel/dahdi.
If you use yum, you can install from repository.
yum -y install kernel-devel
If you run SMP kernel, use instead
yum -y install kernel-smp-devel
Here is what zaptel/dahdi will do to determine if you have the kernel source or not :
- find your kernel version by running uname -r and stock it into $(KVERS)
- set variable $(KSRC) to one of the following /lib/modules/$(KVERS)/build or /usr/src/linux or /usr/src/linux-2.4. The Makefile will then check if one of those directories exist.
- The $(KSRC) directory should contain the .config file.
If you installed the kernel sources, you should have the .config file somewhere in /usr/src/kernels/(somedir)
You just then have to create a symbolic link from /usr/src/linux or /lib/modules/$(KVERS)/build to that directory.
Reconfigure, recompile zaptel/dahdi and asterisk.
Hope it helps


Set password for mysql

mysqladmin -u root password yourrootsqlpassword
mysqladmin -h -u root password yourrootsqlpassword

Nguyen Si Nhan

[Solved] PEAR must be installed

You just install php-pear-DB and php-mysql is Ok.
# yum install php-pear-DB
# yum install php-mysql

Nguyen Si Nhan

Thursday, January 19, 2012

Optimize mysql

# Example MySQL config file for very large systems.
# This is for a large system with memory of 1G-2G where the system runs mainly
# MySQL.
# You can copy this file to
# /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options (in this
# installation this directory is /var/lib/mysql) or
# ~/.my.cnf to set user-specific options.
# In this file, you can use all long options that a program supports.
# If you want to know which options a program supports, run the program
# with the "--help" option.

# The following options will be passed to all MySQL clients
#password = your_password
port = 3306
socket = /var/lib/mysql/mysql.sock

# Here follows entries for some specific programs

# The MySQL server
port = 3306
socket = /var/lib/mysql/mysql.sock
key_buffer = 384M
max_allowed_packet = 16M
table_cache = 1024
sort_buffer_size = 2M
read_buffer_size = 2M
read_rnd_buffer_size = 8M
myisam_sort_buffer_size = 64M
thread_cache_size = 128
query_cache_size = 256M
query_cache_type = 1

#bind-address =
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 8

# Don't listen on a TCP/IP port at all. This can be a security enhancement,
# if all processes that need to connect to mysqld run on the same host.
# All interaction with mysqld must be made via Unix sockets or named pipes.
# Note that using this option without enabling named pipes on Windows
# (via the "enable-named-pipe" option) will render mysqld useless!

# Replication Master Server (default)
# binary logging is required for replication

# required unique id between 1 and 2^32 - 1
# defaults to 1 if master-host is not set
# but will not function as a master if omitted
server-id = 1

# Replication Slave (comment out master section to use this)
# To configure this host as a replication slave, you can choose between
# two methods :
# 1) Use the CHANGE MASTER TO command (fully described in our manual) -
#    the syntax is:
#    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;
#    where you replace <host>, <user>, <password> by quoted strings and
#    <port> by the master's port number (3306 by default).
#    Example:
#    MASTER_USER='joe', MASTER_PASSWORD='secret';
# OR
# 2) Set the variables below. However, in case you choose this method, then
#    start replication for the first time (even unsuccessfully, for example
#    if you mistyped the password in master-password and the slave fails to
#    connect), the slave will create a file, and any later
#    change in this file to the variables' values below will be ignored and
#    overridden by the content of the file, unless you shutdown
#    the slave server, delete and restart the slaver server.
#    For that reason, you may want to leave the lines below untouched
#    (commented) and instead use CHANGE MASTER TO (see above)
# required unique id between 2 and 2^32 - 1
# (and different from the master)
# defaults to 2 if master-host is set
# but will not function as a slave if omitted
#server-id       = 2
# The replication master for this slave - required
#master-host     =   <hostname>
# The username the slave will use for authentication when connecting
# to the master - required
#master-user     =   <username>
# The password the slave will authenticate with when connecting to
# the master - required
#master-password =   <password>
# The port the master is listening on.
# optional - defaults to 3306
#master-port     =  <port>
# binary logging - not required for slaves, but recommended

# Point the following paths to different dedicated disks
#tmpdir = /tmp/
#log-update = /path-to-dedicated-directory/hostname

# Uncomment the following if you are using BDB tables
#bdb_cache_size = 384M
#bdb_max_lock = 100000

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /var/lib/mysql/
#innodb_data_file_path = ibdata1:2000M;ibdata2:10M:autoextend
#innodb_log_group_home_dir = /var/lib/mysql/
#innodb_log_arch_dir = /var/lib/mysql/
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 384M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 100M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

max_allowed_packet = 16M

# Remove the next comment character if you are not familiar with SQL

key_buffer = 256M
sort_buffer_size = 256M
read_buffer = 16M
write_buffer = 16M

key_buffer = 256M
sort_buffer_size = 256M
read_buffer = 16M
write_buffer = 16M


Wednesday, January 18, 2012

Installing Memcache on CentOS


  • Check to make sure that you are running a recent version of CentOS by entering "cat /etc/redhat-release." As of June 2011, the most recent version of CentOS is version 5.6.
  • 2
    Download and setup your system and Memcache to be installed on your server by entering the following commands:
    "cd /user/local/src"
    "curl -O"
    "tar xzvf memcached-1.4.5.tar.gz"
    "cd memcached-1.4.5"
    "LDFLAGS='-W1, --rpath /usr/local/lib' ./configure --prefix=/usr/local"
    These commands move the src directory on your system, download Memcache and set the flags that are required to make Memcache work properly on your system.
  • 3
    Run a simple make install to complete the Memcache installation; the code for this is "make && make install." Please note that you will need root privileges to run this command successfully; this is done in CentOS using the "su" command and entering your root password. Be sure that when the process is completed you "su" back your regular user.
  • 4
    Verify that Memcache is installed properly on your system using the following command: "ps auz | grep memcached." If there are no errors printed in your terminal, then everything is fine with your installation. You can stop Memcache with "pkill memcached."

Monday, January 16, 2012

mysqldump: Error 2013: Lost connection to MySQL server during query when dumping table

Try increasing the value of the max_allowed_packet system variable. Default size is 1MB but it sounds like you are exceeding this. 

To set this add 
(replacing the 64M with whatever value you require) to your config file and restart the server or log into mysql client and issue 
SET GLOBAL max_allowed_packet=67108864

Note: Value in the config file can be followed by M, K to specifiy mb or kb but when using a SET command the value must be given as bytes or as an expression (eg you could specify a 64mb max_allowed_packet using SET GLOBAL max_allowed_packet=64*1024*1024). 

Hopefully this should resolve your problem. 

Sorry forgot to mention that mysqldump also has a max_allowed_packet option and you should try setting this in addition to the above when you run mysqldump. Just start mysqldump with a --max_allowed_packet= option. 


Sunday, January 15, 2012

Tối ưu hóa Blind SQL Injection

Sr vì màu mè khó đọc  laughing

Hôm nay, đi TetCon nguyên 1 ngày. Mình thì ko thật sự hiểu 2 chủ đề Sandbox và Fuzzing.thôi nói chung không phải chuyên ngành mình nên ko ý kiến, dù rằng nghe bảo rất hay big grin

Tóm tắt về cách anh gamma optimize về Blind SQL Injection là thế này.

Dùng find_in_set (về sau thì gamma dùng instr, mình cũng thấy instr hay hơn) để đánh chỉ mục (index). Tức là nếu select find_in_set('a','a,b,c,d...z'); thì nó sẽ trả về1nếu find_in_set('b','a,b,c,d...z') -> 2 .big grin

Kết hợp với Bit-Shifting, ta xác định là dù kí tự gì thì cũng phải 7 query/char (8 bit, nhưng fix ngay bit cao nhất là 0, vì sao thì mở bảng ascii ra xem). Mình cũng đã code ra cái tool này rôi, nhưng cuối cùng chả xài.big grin

Vậy nếu kết hợp 2 cái này lại thì ta sẽ tối ưu đc gì ?. Nếu ta find_in_set đủ các kí tự printable (kí tự in ra đc) thì là: abcdefghijklmnopqrstuvwxyz0123456789_!@#$%^&;*()-+=\."\'~`\\|{}[]:; (khoảng trắng nữa nhé) , tổng cộng là 45 kí tự. vậy nếu ta Bit-shifting cái con số find_in_set trả về thì max cũng chỉ là 45 là 101101 (Bin) , vậy tối đa chỉ có 6 q/s (query/char), còn đối với các số nhỏ hơn thì lại càng ít hơn.

Okie. cơ bản là thế, vậy anh gamma đã tối ưu nó như thế nào ?. Lúc đầu thật sự mình tò mò, ko biết 1 q/s là ntn. Xem qua thì ý tưởng của a khá hay. Tức là ta không còn dùng bit-shifting để tìm ra giá trị find_in_set trả về. mà dùng chính kĩ thuật Time-based SQLI. Anh ấy cho SQL sleep luôn giá trị find_in_set trả về, tức là sleep(find_in_set(.....)) ,thế tức là anh ấy sẽ xem thằng SQL nó "ngủ" bao nhiêu giây thì sẽ ra giá trị find_in_set -> char cần tìm -> 1 q/s/  Clear ? big grin

Ưu điểm thì:
- Ý tưởng và cách khai thác của anh hay big grin
- khả năng bị detect qua log ko cao. vì chỉ có 1 query/ 1 char. thay vì 6 q/s.

Ok. Theo mình thì ý tưởng là hay, nhưng cách này cũng còn vài nhược điểm dễ thấy như:
- Time-based SQLI phụ thuộc rất nhiều vào đường truyền giữa Attacker-Server
- Nếu giá trị find_in_set quá nhỏ thì lại gây nhầm lẫn. về sau a ấy có fix thêm 1 chút là thêm 4-5 kí tự đằng trước để các giá trị nhỏ ko còn nhỏ nữa (tự hiểu đê laughing).
- Nếu giá trị find_in_set quá lớn lại ngủ quá lâu, có thể bị timeout bất cứ lúc nào
- Nói chung ý tưởng của anh thì mình thấy là hay và tốt , nhưng giá trị thực tiễn để áp dụng thì chưa cao lắm. nhưng cũng có thể là a đang gợi ý hoặc cho 1 ý tưởng để các bạn có thể suy nghĩ ra cách khác optimize Blind hay hơn happy.

Nói chung là thế. Nhưng chưa hết, ngày mai mình sẽ viết 1 bài về Optimize Blind SQLI của mình nghĩ ra. Nếu hội tủ vài điều kiện (đ/k này thì ko quá khó, mình nghĩ 90% site bị Blind SQLI sẽ hội tủ đc điều này) thì chỉ cần 2 query / char . Và có thể query song song , tức là có thể dùng cURL cho chạy 2 query 1 lúc -> ko phụ thuộc vào time-based. khả năng bị detect qua log ko cao mấy vì chỉ có 2 query. tốc độ nhanh. Nói chung mai các bạn sẽ biết chi tiết...

Tuesday, January 3, 2012

Directadmin: Compile exim from source

If you have problem with exim such as: can not receive email ,error log return: internal problem in domain_filter router ,you should complile it from source is OK.

In this how-to, we'll outline how to install a fresh exim binary for your system. For compatibilities reasons, we'll make this a non-static binary, as since it's compiled right on your own system, you won't have any library issues.

We'll use exim 4.76 for this example.  Change all occurances of 4.76 to the version you want to use.
tar xvzf exim-4.76.tar.gz
cd exim-4.76/Local
perl -pi -e 's/^EXTRALIBS/#EXTRALIBS/' Makefile
perl -pi -e 's/HAVE_ICONV=yes/HAVE_ICONV=no/' Makefile
cd ..
make install
This will give you a new /usr/sbin/exim-4.76-1 binary which won't be what you want.. you'll need to rename it to /usr/sbin/exim:
cp -f /usr/sbin/exim-4.76-1 /usr/sbin/exim
chmod 4755 /usr/sbin/exim

Remember to restart exim after you're finished.

**Note: If you can't download the exim-4.76.tar.gz from the above link, just go to and find a different link there.  It's the original source, unmodified by us, you can get it anywhere.

You may need to edit the Local/Makefile and remove the iconv section near the top:  HAVE_ICONV=no
if you see this error
rfc2047.o: In function `rfc2047_decode2':
rfc2047.c:(.text+0x395): undefined reference to `libiconv_open'
rfc2047.c:(.text+0x45a): undefined reference to `libiconv'
rfc2047.c:(.text+0x539): undefined reference to `libiconv_close'

For all OS's, you'll also need db4 dev, so type the following on debian
apt-get install libdb4.8-dev libperl-dev libsasl2-dev
or rpm systems:
yum install db4-devel cyrus-sasl-devel
or FreeBSD:
pkg_add -r cyrus-sasl2

If you get perl errors during the compile, you may need to edit the Local/Makefile, and set the values for:

You can generate the values for those options with the following code:
 echo "PERL_CC=`/usr/bin/perl -MConfig -e 'print $Config{cc}'`"
echo "PERL_CCOPTS=`/usr/bin/perl -MExtUtils::Embed -e ccopts`"
echo "PERL_LIBS=`/usr/bin/perl -MExtUtils::Embed -e ldopts`"
Sample values for FreeBSD 7:
PERL_CCOPTS= -DAPPLLIB_EXP="/usr/local/lib/perl5/5.8.8/BSDPAN" -DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include  -I/usr/local/lib/perl5/5.8.8/mach/CORE
PERL_LIBS=  -Wl,-R/usr/local/lib/perl5/5.8.8/mach/CORE  -Wl,-E -L/usr/local/lib /usr/local/lib/perl5/5.8.8/mach/auto/DynaLoader/DynaLoader.a -L/usr/local/lib/perl5/5.8.8/mach/CORE -lperl -lm -lcrypt -lutil
Sample values for Debian 4:
PERL_CCOPTS= -D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64  -I/usr/lib/perl/5.8/CORE
PERL_LIBS=-Wl,-E  -L/usr/local/lib /usr/lib/perl/5.8/auto/DynaLoader/DynaLoader.a -L/usr/lib/perl/5.8/CORE -ldl -lm -lpthread -lc -lcrypt
On debian, if you're missing any requird modules, without actually installing "exim4", you can use:
apt-get build-dep exim4
to install all dependancies that exim needs to compile, without installing the apt-get version of exim itself.

Debian 5 requires the libperl5.10 module. If you don't have it:
apt-get install libperl5.10
The above code will resolve the error:
exim: error while loading shared libraries: cannot open shared object file: No such file or directory