Tugriceri Web Notes

Security

StrongSwan and Android configs

by on Apr.27, 2013, under Linux, Security, StrongSwan

root@six #cat ipsec.conf

conn tugriceri.com
leftsubnet=0.0.0.0/0
left=209.208.63.204
leftcert=/cert/strongswan.pem
leftauth=pubkey
leftsendcert=yes
leftid=six.tugriceri.com
right=%any
rightid=%any
rightsourceip=10.0.5.0/24
rightauth=eap-mschapv2
rightsendcert=never
eap_identity=%any
auto=add

root@six #cat ipsec.secrets

# strongSwan IPsec secrets file
: RSA /cert/strongswan.key
six.tugriceri.com : RSA /cert/strongswan.key
testuser : EAP "secretpass"

root@six #cat openssl-req.cfg

[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name
prompt = no

[ v3_req ]

# Extensions to add to a certificate request

#keyUsage = nonRepudiation, digitalSignature, keyEncipherment
subjectAltName = "DNS:six.tugriceri.com,DNS:www.tugriceri.com,IP:209.208.63.204,DNS:tugriceri.com"
#subjectAltName = @alt_names

[alt_names]
DNS.1 = six.tugriceri.com
DNS.2 = www.tugriceri.com

[ req_distinguished_name ]
CN = six.tugriceri.com
GN = six.tugriceri.com
OU = Tugriceri.com
O = Tugriceri.com
L = Istanbul
ST = Istanbul
C = TR
emailAddress = root@tugriceri.com
subjectAltName = six.tugriceri.com

subjectAltName is importend point of configuration. Your certificate must be have this.

root@six #cat certyarat.sh

rm -f strongswan.req
rm -f strongswan.pem
openssl req -new -out strongswan.req -key strongswan.key -config openssl-req.cfg
openssl ca -batch -notext -in strongswan.req -out strongswan.pem -config ca.conf

root@six #cat showcert

openssl x509 -in strongswan.pem -text -noout
Command Output :
X509v3 extensions:
X509v3 Basic Constraints:
CA:FALSE
X509v3 Subject Alternative Name:
DNS:six.tugriceri.com, DNS:www.tugriceri.com, IP Address:209.208.63.204, DNS:tugriceri.com

root@six #cat ca.conf

[ ca ]
default_ca = tugricerica
[ tugricerica ]
copy_extensions = copy
#Removed lines

copy_extension must be in your ca.conf

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SELinux FTP Home dir write permission

by on Oct.07, 2011, under Linux, Security, SELinux

Connected to 127.0.0.1.
220 (vsFTPd 2.2.2)
530 Please login with USER and PASS.
530 Please login with USER and PASS.
KERBEROS_V4 rejected as an authentication type
Name (127.0.0.1:root): test1
331 Please specify the password.
Password:
500 OOPS: cannot change directory:/var/ftp/test1
Login failed.
ftp> quit

[root@legion mnt]# getsebool ftp_home_dir
ftp_home_dir –> off
[root@legion mnt]# setsebool -P ftp_home_dir 1
[root@legion mnt]# getsebool ftp_home_dir
ftp_home_dir –> on

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Deny user for remote login

by on Jun.06, 2011, under Linux, Security

sudo vi /etc/security/access.conf

-:root:ALL EXCEPT LOCAL

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SSL Weak Cipher and SSLv2 tests

by on Jan.22, 2011, under Security

echo ‘GET HTTP/1.0’ | openssl s_client -ssl3 -cipher LOW -connect www.tugriceri.com:443
echo ‘GET HTTP/1.0’ | openssl s_client -ssl2 -cipher LOW -connect www.tugriceri.com:443
echo ‘GET HTTP/1.0’ | openssl s_client -ssl2 -connect www.tugriceri.com:443

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uvscan process is too slow

by on Nov.26, 2010, under Antivirus, Security

# time uvscan –version
McAfee VirusScan Command Line for Linux64 Version: 6.0.3.356
Copyright (C) 2010 McAfee, Inc.
(408) 988-3832 LICENSED COPY – November 26 2010

AV Engine version: 5400.1158 for Linux64.
Dat set version: 5985 created May 17 2010
Scanning for 619012 viruses, trojans and variants.

real    0m9.501s
user    0m9.365s
sys     0m0.132s

# uvscan –decompress
McAfee VirusScan Command Line for Linux64 Version: 6.0.3.356
Copyright (C) 2010 McAfee, Inc.
(408) 988-3832 LICENSED COPY – November 26 2010

AV Engine version: 5400.1158 for Linux64.
Dat set version: 5985 created May 17 2010
Scanning for 619012 viruses, trojans and variants.

This program is more than 5 months old. New viruses come out all the
time – we would suggest that you upgrade your copy.

Time: 00:00.00

# time uvscan –version
McAfee VirusScan Command Line for Linux64 Version: 6.0.3.356
Copyright (C) 2010 McAfee, Inc.
(408) 988-3832 LICENSED COPY – November 26 2010

AV Engine version: 5400.1158 for Linux64.
Dat set version: 5985 created May 17 2010
Scanning for 619012 viruses, trojans and variants.

real    0m2.801s
user    0m2.664s
sys     0m0.135s

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crt to der

by on Apr.30, 2010, under Security

openssl x509 -in auth_tugriceri_com.crt -out auth_tugriceri_com.der -outform DER

openssl rsa -in www_tugriceri_com.key -outform DER -out www_tugriceri_com-der.key

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Sftp chroot settings

by on Oct.17, 2009, under Security, SSH

cat /etc/ssh/sshd_config

Subsystem sftp internal-sftp

Match group sftponly
         ChrootDirectory /chroot
         X11Forwarding no
         AllowTcpForwarding no
         ForceCommand internal-sftp

cat /etc/passwd
testuser:x:500:504::/:/bin/bash
sftponly:x:504:testuser

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run command via ssh (remote)

by on Apr.08, 2009, under Linux, Security, Shell

cat ls_keykur.sh | ssh root@10.94.12.3
ssh root@10.94.12.3 “date”

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other ssl issue with my own ca

by on Mar.18, 2009, under Security

/root/tugriceri.com_CA/ca/
cat ca.conf
[ ca ]
default_ca = ca_default
[ ca_default ]
dir = /root/tugriceri.com_CA/ca/
certs = /root/tugriceri.com_CA/ca/
new_certs_dir = /root/tugriceri.com_CA/ca/ca.db.certs
database = /root/tugriceri.com_CA/ca/ca.db.index
serial = /root/tugriceri.com_CA/ca/ca.db.serial
RANDFILE = /root/tugriceri.com_CA/ca/ca.db.rand
certificate = /root/tugriceri.com_CA/ca/ca.crt
private_key = /root/tugriceri.com_CA/ca/ca.key
default_days = 365
default_crl_days = 30
default_md = md5
preserve = no
policy = generic_policy
[ generic_policy ]
countryName = optional
stateOrProvinceName = optional
localityName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional

openssl ca -config ca.conf -notext -out one.tugriceri.com/one.tugriceri.com.cer -infiles one.tugriceri.com/one.tugriceri.com.csr

openssl x509 -req -days 365 -in one.tugriceri.com/one.tugriceri.com.csr -CA ca/ca.crt -CAkey ca/ca.key -CAcreateserial -out one.tugriceri.com/one.tugriceri.com.cer

openssl verify -CAfile ../ca/ca.crt one.tugriceri.com.cer

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pfx to key

by on Feb.03, 2009, under Security

openssl pkcs12 -export -in my.pem -nodes -out my.pfx
openssl pkcs12 -in my.pfx -out my-nodes.key -nodes -nocerts

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Cisco SSH Configuration

by on Jan.12, 2009, under Cisco, Network, Security

conf# username cagri privilege 15 secret cisco

“creates a user in local database with privelege level 15 and encrypted password cisco”

conf#ip domain-name tugriceri.com

“sets a domain name for the device”

conf#crypto key generate rsa

“creates a rsa key. in the next step encryption bits will be asked. default is 512. 1024 is better”

conf#ip ssh version 2

“change the version of ssh to 2”

conf#line vty 0 4

“go under the virtual teletype ports”

conf-line#transport input ssh

“and change the login type from telnet to ssh”

conf-line#login local

“device will look at the local user database to log in a user”

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ssh Tunnel

by on Dec.07, 2008, under Security

shell# ssh -f root@192.168.2.54 -L 7200:192.168.2.54:7200 -N

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Bir Asa log u

by on Oct.04, 2008, under Firewalls, Security

Routing failed to locate next hop for icmp from outside…

Net1 de olması gereken bir host yada network net2 de tanımlanmış ise bu log ile karşılaşılır.  Host u fln silip doğru yerde tanımlarını yapmak lazım.

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Cisco Asa ssh enable

by on Oct.03, 2008, under Firewalls, Security

username emre password pas priv 15
aaa authentication ssh console LOCAL

ssh x.x.x.x x.x.x.x external

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mysql deki snort loglarini temizlemek

by on Sep.21, 2008, under Mysql, Security

reset master
purge master logs
delete from data
delete from event where timestamp<‘2008-8-01’

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Sudo requiretty settings

by on Jan.08, 2008, under Security

sudo:   apache : sorry, you must have a tty to run sudo ; TTY=unknown ; …

/var/log/secure içerisinde gözlemlenen bu log apache ile çağırılan bir sistem komutunun çalışmayıp verdiği uyarı log u .

sudoers içerisinde

Defaults    requiretty

ayarının # lenmesi gerekmektedir. Yukarıdaki log danda görüldüğü gibi apache user i herhangi bir tty ye sahip olmadığı için bu log düşmektedir. Normal şartlarda zaten “requiretty” nin kapatılmasına gerek yok fakat php kullanarak root yetkilerinde bir komut çalıştırma ihtiyacınız olursa bu ayarı kapatmanız gerekecektir.

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SSL sertifikası yaratma

by on Jan.04, 2008, under Security

Openssl ile sertifika yaratmak için yarattığınız anahtar dosya da güçlü şifreleme methodlarından birini seçerseniz sizden bir şifre girmenizi isteyecektir. Apache nin her başlamasında bu şifreyi yazmanız gerekmektedir.
Şifre sorulmadan bir sertifika yaratmak için ;

shell #> openssl dsaparam 1024 -out dsadosyasi

“dsaparam DSA Parameter Generation.”

shell #> openssl gendsa -out webserver.key dsadosyasi

Bu aşamada sizden şifre istenmeden bir key dosyasi yaratılacaktır. Bir şifre vermek isterseniz -des3 parametresi ekleyerek 3des algoritması ile şifrelenmiş bir anahtar dosya yaratabilirsiniz.

Sertifika talep dosyası yaratmak için ;
shell #> openssl req -new -key webserver.key -out webserver.csr

webserver.csr bizim sertifika talep dosyamız. Bu dosyayı kendi CA imizde yada Verisign gibi trusted CA lerde imzalatıp kullanabiliriz.

Kendi CA server imizda imzalamak için

shell #> openssl x509 -req -days 365 -in webserver.csr -signkey webserver.key -out webserver.crt

apache içerisinde ;

<VirtualHost _default_:443>
ServerAdmin root@tugriceri.com
DocumentRoot /var/www/html/
ServerName mail.tugriceri.com
SSLEngine on
SSLCertificateFile /webmail/webserver.crt
SSLCertificateKeyFile /webmail/webserver.key
#SSLCACertificateFile /webmail/cacertnew.pem
SetEnvIf User-Agent “.*MSIE.*” nokeepalive ssl-unclean-shutdown
</VirtualHost>

_default_ webserver inizin default ip adresidir. Her sertifika için başka ip ler vermeniz gerekmektedir. Bu sebepten diğer virtual host lar için _default_ yerine ip adresinizi yazabilirsiniz.

Eğer CA server başka bir sunucunuzun üzerinde ise SSLCACertificateFile ile CA sertifikanızı apache ye gösterebilir yada ;

shell #> keytool -import -file /webmail/cacertnew.pem

ile default key store içerisinde ekleyebilirsiniz.

Örnek;
openssl genrsa -des3 -rand file1:file2:file3:file4:file5 -out server.key 1024
openssl rsa -in server.key -out server.pem
openssl req -new -key server.key -out server.csr
openssl x509 -req -days 60 -in server.csr -signkey server.key -out server.crt

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Cer to Pem

by on Jan.04, 2008, under Security

You can convert cer file to pem with this example command.

openssl x509 -in certnewb.cer -inform DER -out certnewb.pem -outform PEM

if you have a Microsoft CA server and if you signed your certification request with this CA server, this server will give to you der encoded certnew.cer file. you can convert this file to pem format for the any apache server.

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Php safe_mode

by on Sep.23, 2007, under Security

php_admin_flag safe_mode On

safe_mode ile php, script in sahibi ile erişilmeye çalışılan dosya sahibini kontrol eder.

Belirli bir directory deki scr çalışmaması için.

<Directory /home/www/blabla/ >
php_admin_flag engine off
</Directory>

Aynı şekilde safe_mode da uygulanabilir.

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