Improving Web Application Security: Threats and - CGISecurity

148 Part III: Building Secure Web ApplicationsVulnerabilitiesVulnerabilities that can lead to code injection include:● Poor input validation, particularly where your assembly calls intounmanaged code● Accepting delegates from partially trusted code● Over-privileged process accountsAttacksCommon code injection attacks include:● Buffer overflows● Invoking a delegate from an untrusted sourceCountermeasuresCountermeasures that you can use to prevent code injection include:●●●●●Validate input parameters.Validate data passed to unmanaged APIs.Do not accept delegates from untrusted sources.Use strongly typed delegates and deny permissions before calling the delegate.To further reduce risk, run assemblies using least privileged accounts.Information DisclosureAssemblies can suffer from information disclosure if they leak sensitive data such asexception details and clear text secrets to legitimate and malicious users alike. It isalso easier to reverse engineer an assembly’s Microsoft Intermediate Language(MSIL) into source code than it is with binary machine code. This presents a threat tointellectual property.VulnerabilitiesVulnerabilities that can lead to information disclosure include:● Weak or no formal exception handling● Hard-coded secrets in codeAttacksCommon attacks include:● Attempting to cause errors by passing malformed input to the assembly●Using ILDASM on an assembly to steal secrets