Improper cleanup on thrown exception

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This is a Vulnerability. To view all vulnerabilities, please see the Vulnerability Category page.



ASDR Table of Contents

Last revision (mm/dd/yy): 02/17/2009

Description

Causing a change in flow, due to an exception, can often leave the code in a bad state.

Consequences

  • Implementation: The code could be left in a bad state.

Exposure period

  • Implementation: Many logic errors can lead to this condition.

Platform

  • Languages: Java, C, C# or any language which can throw an exception.
  • Operating platforms: Any

Required resources

Any

Severity

Medium

Likelihood of exploit

Medium

Often, when functions or loops become complicated, some level of cleanup in the beginning to the end is needed. Often, since exceptions can disturb the flow of the code, one can leave a code block in a bad state.


Risk Factors

TBD

Examples

In C++/Java:

public class foo {
  public static final void main( String args[] ) {
        boolean returnValue;
        returnValue=doStuff();
  }
  public static final boolean doStuff( ) {
        boolean threadLock;
        boolean truthvalue=true;

        try {
                while(//check some condition){
                        threadLock=true;
                        //do some stuff to truthvalue
                        threadLock=false;
                }
        } catch (Exception e){
                System.err.println("You did something bad");
                        if (something) return truthvalue;
        }
        return  truthvalue;
  }
}

In this case, you may leave a thread locked accidentally.


Related Attacks


Related Vulnerabilities


Related Controls

  • Implementation: If one breaks from a loop or function by throwing an exception, make sure that cleanup happens or that you should exit the program. Use throwing exceptions sparsely.

Related Technical Impacts


References

TBD