The US Internal Revenue Service is putting tax payers at risk by operating thousands of web servers that contain security vulnerabilities or have not received proper authorization, a new report has concluded.

According to the Treasury Inspector for the Tax Administration - a Treasury Department watchdog - the IRS operates 2,093 web servers with at least one vulnerability. It said 540 of those servers contained one or more vulnerabilities rated high risk. The report identified 1,811 internal servers that had not been approved to connect to the network. Some 1,150 of those were being used for non-business purposes.

Under IRS rules, all internal websites and servers must be registered with the agency's Modernization and Information Technology Services organization.

"Unauthorized servers pose a greater risk because the IRS has no way to ensure that they will be continually configured in accordance with security standards and patched when new vulnerabilities are identified," the report's authors wrote. "Malicious hackers or employees could exploit the vulnerabilities on these web servers to manipulate data on the servers or to use the servers as launch points to attack other computers connected to the network."

Examples of high-risk vulnerabilities included buffer overflow weaknesses and servers that used blank passwords. The authors blamed the vulnerabilities on employees who failed to carry out duties as required.

The report offered five recommendations that included assigning responsibility for registration of specific servers, the blocking of unauthorized servers from the IRS network and an annual scan of the network to identify all machines that are connected.

The full report is available here. ®