Log data is essential in the investigation of events. The accuracy of the information is always pertinent. Information that is not accurate does not help in the revealing of potential security risks and may hinder the early discovery of a system compromise. One of the first steps an attacker will undertake is the modification or deletion of log records to cover his tracks and prolong discovery. The web server must protect the log data from unauthorized modification. This can be done by the web server if the web server is also doing the logging function. The web server may also use an external log system. In either case, the logs must be protected from modification by non-privileged users.
Review the web server documentation and deployed configuration settings to determine if the web server logging features protect log information from unauthorized modification. Review file system settings to verify the log files have secure file permissions. If the web server log files are not protected from unauthorized modification, this is a finding.
Configure the web server log files so unauthorized modification of log information is not possible.