Configuration Management

Configuration Management

Many applications support configuration management interfaces and functionality to allow operators and administrators to change configuration parameters, update Web site content, and to perform routine maintenance. Top configuration management threats include:

Unauthorized Access to Administration Interfaces
Administration interfaces are often provided through additional Web pages or separate Web applications that allow administrators, operators, and content developers to managed site content and configuration. Administration interfaces such as these should be available only to restricted and authorized users. Malicious users able to access a configuration management function can potentially deface the Web site, access downstream systems and databases, or take the application out of action altogether by corrupting configuration data.

Countermeasures to prevent unauthorized access to administration interfaces include:
● Minimize the number of administration interfaces.
● Use strong authentication, for example, by using certificates.
● Use strong authorization with multiple gatekeepers.
● Consider supporting only local administration. If remote administration is absolutely essential, use encrypted channels, for example, with VPN technology or SSL, because of the sensitive nature of the data passed over administrative interfaces. To further reduce risk, also consider using IPSec policies to limit remote administration to computers on the internal network.

Unauthorized Access to Configuration Stores
Because of the sensitive nature of the data maintained in configuration stores, you should ensure that the stores are adequately secured.

Countermeasures to protect configuration stores include:
● Configure restricted ACLs on text-based configuration files such as Machine.config and Web.config.
● Keep custom configuration stores outside of the Web space. This removes the potential to download Web server configurations to exploit their vulnerabilities.

Retrieval of Plaintext Configuration Secrets
Restricting access to the configuration store is a must. As an important defense in depth mechanism, you should encrypt sensitive data such as passwords and connection strings. This helps prevent external attackers from obtaining sensitive configuration data. It also prevents rogue administrators and internal employees from obtaining sensitive details such as database connection strings and account credentials that might allow them to gain access to other systems.

Lack of Individual Accountability
Lack of auditing and logging of changes made to configuration information threatens the ability to identify when changes were made and who made those changes. When a breaking change is made either by an honest operator error or by a malicious change to grant privileged access, action must first be taken to correct the change. Then apply preventive measures to prevent breaking changes to be introduced in the same manner. Keep in mind that auditing and logging can be circumvented by a shared account; this applies to both administrative and user/application/service accounts. Administrative accounts must not be shared. User/application/service accounts must be assigned at a level that allows the identification of a single source of access using the account, and that contains any damage to the privileges granted that account.

Over-privileged Application and Service Accounts
If application and service accounts are granted access to change configuration information on the system, they may be manipulated to do so by an attacker. The risk of this threat can be mitigated by adopting a policy of using least privileged service and application accounts. Be wary of granting accounts the ability to modify their own configuration information unless explicitly required by design.

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