CWE-228: Improper Handling of Syntactically Invalid Structure
Weakness ID: 228
Abstraction: Class Structure: Simple
Status: Incomplete
Presentation Filter:
Description
The product does not handle or incorrectly handles input that is not syntactically well-formed with respect to the associated specification.
Relationships
The table(s) below shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.
Relevant to the view "Research Concepts" (CWE-1000)
Nature
Type
ID
Name
ChildOf
Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More general than a Base weakness.
Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More general than a Base weakness.
Base - a weakness that is described in an abstract fashion, but with sufficient details to infer specific methods for detection and prevention. More general than a Variant weakness, but more specific than a Class weakness.
Base - a weakness that is described in an abstract fashion, but with sufficient details to infer specific methods for detection and prevention. More general than a Variant weakness, but more specific than a Class weakness.
Base - a weakness that is described in an abstract fashion, but with sufficient details to infer specific methods for detection and prevention. More general than a Variant weakness, but more specific than a Class weakness.
Base - a weakness that is described in an abstract fashion, but with sufficient details to infer specific methods for detection and prevention. More general than a Variant weakness, but more specific than a Class weakness.
Base - a weakness that is described in an abstract fashion, but with sufficient details to infer specific methods for detection and prevention. More general than a Variant weakness, but more specific than a Class weakness.
Base - a weakness that is described in an abstract fashion, but with sufficient details to infer specific methods for detection and prevention. More general than a Variant weakness, but more specific than a Class weakness.
Base - a weakness that is described in an abstract fashion, but with sufficient details to infer specific methods for detection and prevention. More general than a Variant weakness, but more specific than a Class weakness.
Base - a weakness that is described in an abstract fashion, but with sufficient details to infer specific methods for detection and prevention. More general than a Variant weakness, but more specific than a Class weakness.
The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the software life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.
Phase
Note
Implementation
Architecture and Design
Common Consequences
The table below specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
If an input is syntactically invalid, then processing the input could place the system in an unexpected state that could lead to a crash, consume available system resources or other unintended behaviors.
Demonstrative Examples
Example 1
This application has registered to handle a URL when sent an intent:
(bad code)
Example Language: Java
... IntentFilter filter = new IntentFilter("com.example.URLHandler.openURL"); MyReceiver receiver = new MyReceiver(); registerReceiver(receiver, filter); ...
public class UrlHandlerReceiver extends BroadcastReceiver {
@Override public void onReceive(Context context, Intent intent) {
String URL = intent.getStringExtra("URLToOpen"); int length = URL.length();
... }
}
}
The application assumes the URL will always be included in the intent. When the URL is not present, the call to getStringExtra() will return null, thus causing a null pointer exception when length() is called.
Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).
This entry needs more investigation. Public vulnerability research generally focuses on the manipulations that generate invalid structure, instead of the weaknesses that are exploited by those manipulations. For example, a common attack involves making a request that omits a required field, which can trigger a crash in some cases. The crash could be due to a named chain such as CWE-690 (Unchecked Return Value to NULL Pointer Dereference), but public reports rarely cover this aspect of a vulnerability.
Maintenance
The validity of input could be roughly classified along "syntactic", "semantic", and "lexical" dimensions. If the specification requires that an input value should be delimited with the "[" and "]" square brackets, then any input that does not follow this specification would be syntactically invalid. If the input between the brackets is expected to be a number, but the letters "aaa" are provided, then the input is syntactically invalid. If the input is a number and enclosed in brackets, but the number is outside of the allowable range, then it is semantically invalid. The inter-relationships between these properties - and their associated weaknesses- need further exploration.
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Page Last Updated:
March 29, 2018
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