Reachable Assertion

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.


Description

While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service.

For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

In the excerpt below, an AssertionError (an unchecked exception) is thrown if the user hasn't entered an email address in an HTML form.

String email = request.getParameter("email_address");
assert email != null;

See Also

SEI CERT Oracle Secure Coding Standard for Java - Guidelines 06. Methods (MET)

Weaknesses in this category are related to the rules and recommendations in the Methods (MET) section of the SEI CERT Oracle Secure Coding Standard for Java.

SFP Secondary Cluster: Use of an Improper API

This category identifies Software Fault Patterns (SFPs) within the Use of an Improper API cluster (SFP3).

Error Conditions, Return Values, Status Codes

This category includes weaknesses that occur if a function does not generate the correct return/status code, or if the application does not handle all possible return/...

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

CWE Cross-section

This view contains a selection of weaknesses that represent the variety of weaknesses that are captured in CWE, at a level of abstraction that is likely to be useful t...

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.


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