Sending non-cloned mutable data as an argument may result in
that data being altered or deleted by the called function, thereby putting the
calling function into an undefined state.
Time of Introduction
Implementation
Applicable Platforms
Languages
C
C++
Java
.NET
Common Consequences
Scope
Effect
Integrity
Potentially data could be tampered with by another function which
should not have been tampered with.
Likelihood of Exploit
Medium
Demonstrative Examples
Example 1
(Bad Code)
C and C++
private: int foo. complexType bar;
String baz;
otherClass externalClass;
public: void doStuff() {
externalClass.doOtherStuff(foo, bar, baz)
}
In this example, bar and baz will be passed by reference to
doOtherStuff() which may change them.
Potential Mitigations
Phase
Description
Implementation
Pass in data which should not be altered as constant or
immutable.
Implementation
Clone all mutable data before returning references to it. This is the
preferred mitigation. This way -- regardless of what changes are made to
the data -- a valid copy is retained for use by the class.
Other Notes
In situations where unknown code is called with references to mutable
data, this external code may possibly make changes to the data sent. If this
data was not previously cloned, you will be left with modified data which
may, or may not, be valid in the context of execution.
Description
