Mar 25 2015

How to Change SSH Port When Selinux is Enable on Oracle Linux 7

Category: Linux & Unix,System SecurityFatih Acar @ 15:47

SSH service runs on 22 port number. You can change this port number for security. If you use Oracle Linux 7, Centos 7 or Red Hat Linux 7 versions, you can change port number with below operations. If selinux is enabled, you have to add new port number to selinux configuration because of the fact that selinux allows only 22 port number for ssh connections.

Step 1 : Change Port Number

[root #] vi /etc/ssh/sshd_config
Port 2290

Save and Exit

Step 2 : Change Selinux Configuration

To change:
[root #] semanage port -a -t ssh_port_t -p tcp 2290
To list:
[root #] semanage port -l | grep ssh

Step 3 : Add New Port to Firewall

To Add:
[root #] firewall-cmd –permanent –zone=public –add-port=2290/tcp
To Activate
[root #] firewall-cmd –reload

Step 4 : Restart SSHD Service to Activate New SSH Confiuration

[root #] systemctl restart sshd.service

Step 5 : Show Running SSH Port

[root #] ss -tnlp | grep ssh

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Feb 04 2014

SAP Security Audit Log Activation

Category: SAP Basis,System SecurityFatih Acar @ 14:52

As of Release 4.0, you can use the Security Audit Log to record security-related system information such as changes to user master records or unsuccessful logon attempts. This log is a tool designed for auditors who need to take a detailed look at what occurs in the SAP System. By activating the audit log, you keep a record of those activities that you specify for your audit. You can then access this information for evaluation in the form of an audit analysis report.
The Security Audit Log provides for long-term data access. The audit files are retained until you explicitly delete them. Currently, the Security Audit Log does not support the automatic archiving of the log files; however, you can manually archive them at any time.

SAP Security Audit Log

You can record the following information in the Security Audit Log

  • Successful and unsuccessful dialog logon attempts
  • Successful and unsuccessful RFC logon attempts
  • RFC calls to function modules
  • Changes to user master records
  • Successful and unsuccessful transaction starts
  • Changes to the audit configuration

SAP Security Audit Log Activation Steps

1 – Create Profile

Tcode > SM19

SAP Security Audit Log 1

SAP Security Audit Log 1

SAP Security Audit Log 2

SAP Security Audit Log 2

Continue reading “SAP Security Audit Log Activation”

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Tags: SAP Basis, SAP Security Audit Log, Sap System Administration, System Administration, System Security

Apr 29 2013

Disable root SSH Login on Linux Server

Category: Database Security,Linux & Unix,System SecurityFatih Acar @ 10:45

Root user is the most authoritative user on linux operating systems. You can take measure for security with disable root ssh. You can connect to server with other users.

Edit sshd_config

vi /etc/ssh/sshd_config

#LoginGraceTime 2m
#PermitRootLogin yes
#StrictModes yes

Note : “PermitRootLogin yes” is default value. This value allows ssh root login
You have to change parameter and remove # symbol.

#LoginGraceTime 2m
PermitRootLogin no
#StrictModes yes

Edit Port

Note : You can change ssh connection port, then you can provide extra security.

vi /etc/ssh/sshd_config

Change port number


Restart sshd Service

service sshd restart

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Tags: Database Security, System Administration, System Security

Dec 16 2011

Social Engineering Attacks

Category: Database Security,Information Security,System SecurityFatih Acar @ 17:07

All social engineering techniques are based on specific attributes of human decision-making known as cognitive biases. These biases, sometimes called “bugs in the human hardware,” are exploited in various combinations to create attack techniques, some of which are listed here:


Pretexting is the act of creating and using an invented scenario (the pretext) to engage a targeted victim in a manner that increases the chance the victim will divulge information or perform actions that would be unlikely in ordinary circumstances.[4] An elaborate lie, it most often involves some prior research or setup and the use of this information for impersonation (e.g., date of birth, Social Security Number, last bill amount) to establish legitimacy in the mind of the target.
This technique can be used to blame a business into disclosing customer information as well as by private investigators to obtain telephone records, utility records, banking records and other information directly from company service representatives. The information can then be used to establish even greater legitimacy under tougher questioning with a manager, e.g., to make account changes, get specific balances, etc.
Pretexting can also be used to impersonate co-workers, police, bank, tax authorities, clergy, insurance investigators — or any other individual who could have perceived authority or right-to-know in the mind of the targeted victim. The pretexter must simply prepare answers to questions that might be asked by the victim. In some cases all that is needed is a voice that sounds authoritative, an earnest tone, and an ability to think on one’s feet.

Diversion theft

Diversion theft, also known as the “Corner Game” or “Round the Corner Game”, originated in the East End of London.
In summary, diversion theft is a “con” exercised by professional thieves, normally against a transport or courier company. The objective is to persuade the persons responsible for a legitimate delivery that the consignment is requested elsewhere — hence, “round the corner”.
With a load/consignment redirected, the thieves persuade the driver to unload the consignment near to, or away from, the consignee’s address, in the pretense that it is “going straight out” or “urgently required somewhere else”.
The “con” or deception has many different facets, which include social engineering techniques to persuade legitimate administrative or traffic personnel of a transport or courier company to issue instructions to the driver to redirect the consignment or load.
Another variation of diversion theft is stationing a security van outside a bank on a Friday evening. Smartly dressed guards use the line “Night safe’s out of order, Sir”. By this method shopkeepers etc. are gulled into depositing their takings into the van. They do of course obtain a receipt but later this turns out to be worthless. A similar technique was used many years ago to steal a Steinway grand piano from a radio studio in London. “Come to overhaul the piano, guv” was the chat line.

Continue reading “Social Engineering Attacks”

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Tags: Oracle, System Security