CWE-390: Detection of Error Condition Without Action
Weakness ID: 390
Vulnerability Mapping:ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities Abstraction:
BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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Description
The product detects a specific error, but takes no actions to handle the error.
Common Consequences
This table 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.
Scope
Impact
Likelihood
Integrity Other
Technical Impact: Varies by Context; Unexpected State; Alter Execution Logic
An attacker could utilize an ignored error condition to place the system in an unexpected state that could lead to the execution of unintended logic and could cause other unintended behavior.
Potential Mitigations
Phase: Implementation
Properly handle each exception. This is the recommended solution. Ensure that all exceptions are handled in such a way that you can be sure of the state of your system at any given moment.
Phase: Implementation
If a function returns an error, it is important to either fix the problem and try again, alert the user that an error has happened and let the program continue, or alert the user and close and cleanup the program.
Phase: Testing
Subject the product to extensive testing to discover some of the possible instances of where/how errors or return values are not handled. Consider testing techniques such as ad hoc, equivalence partitioning, robustness and fault tolerance, mutation, and fuzzing.
Relationships
This table 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 specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.
Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
This table 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 "Software Development" (CWE-699)
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
This table 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 "Architectural Concepts" (CWE-1008)
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
The different Modes of Introduction provide information
about how and when this
weakness may be introduced. The Phase identifies a point in the life cycle at which
introduction
may occur, while the Note provides a typical scenario related to introduction during the
given
phase.
Phase
Note
Implementation
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Applicable Platforms
This listing shows possible areas for which the given
weakness could appear. These
may be for specific named Languages, Operating Systems, Architectures, Paradigms,
Technologies,
or a class of such platforms. The platform is listed along with how frequently the given
weakness appears for that instance.
Languages
Class: Not Language-Specific
(Undetermined Prevalence)
Likelihood Of Exploit
Medium
Demonstrative Examples
Example 1
The following example attempts to allocate memory for a character. After the call to malloc, an if statement is used to check whether the malloc function failed.
(bad code)
Example Language: C
foo=malloc(sizeof(char)); //the next line checks to see if malloc failed if (foo==NULL) {
//We do nothing so we just ignore the error.
}
The conditional successfully detects a NULL return value from malloc indicating a failure, however it does not do anything to handle the problem. Unhandled errors may have unexpected results and may cause the program to crash or terminate.
Instead, the if block should contain statements that either attempt to fix the problem or notify the user that an error has occurred and continue processing or perform some cleanup and gracefully terminate the program. The following example notifies the user that the malloc function did not allocate the required memory resources and returns an error code.
(good code)
Example Language: C
foo=malloc(sizeof(char)); //the next line checks to see if malloc failed if (foo==NULL) {
printf("Malloc failed to allocate memory resources"); return -1;
}
Example 2
In the following C++ example the method readFile() will read the file whose name is provided in the input parameter and will return the contents of the file in char string. The method calls open() and read() may result in errors if the file does not exist or does not contain any data to read. These errors will be thrown when the is_open() method and good() method indicate errors opening or reading the file. However, these errors are not handled within the catch statement. Catch statements that do not perform any processing will have unexpected results. In this case an empty char string will be returned, and the file will not be properly closed.
(bad code)
Example Language: C++
char* readfile (char *filename) {
try {
// open input file ifstream infile; infile.open(filename);
if (!infile.is_open()) {
throw "Unable to open file " + filename;
}
// get length of file infile.seekg (0, ios::end); int length = infile.tellg(); infile.seekg (0, ios::beg);
// allocate memory char *buffer = new char [length];
// read data from file infile.read (buffer,length);
if (!infile.good()) {
throw "Unable to read from file " + filename;
}
infile.close();
return buffer;
} catch (...) {
/* bug: insert code to handle this later */
}
}
The catch statement should contain statements that either attempt to fix the problem or notify the user that an error has occurred and continue processing or perform some cleanup and gracefully terminate the program. The following C++ example contains two catch statements. The first of these will catch a specific error thrown within the try block, and the second catch statement will catch all other errors from within the catch block. Both catch statements will notify the user that an error has occurred, close the file, and rethrow to the block that called the readFile() method for further handling or possible termination of the program.
(good code)
Example Language: C++
char* readFile (char *filename) {
try {
// open input file ifstream infile; infile.open(filename);
if (!infile.is_open()) {
throw "Unable to open file " + filename;
}
// get length of file infile.seekg (0, ios::end); int length = infile.tellg(); infile.seekg (0, ios::beg);
// allocate memory char *buffer = new char [length];
// read data from file infile.read (buffer,length);
printf("Error occurred trying to read from file \n"); infile.close(); throw;
}
}
Example 3
In the following Java example the method readFile will read the file whose name is provided in the input parameter and will return the contents of the file in a String object. The constructor of the FileReader object and the read method call may throw exceptions and therefore must be within a try/catch block. While the catch statement in this example will catch thrown exceptions in order for the method to compile, no processing is performed to handle the thrown exceptions. Catch statements that do not perform any processing will have unexpected results. In this case, this will result in the return of a null String.
(bad code)
Example Language: Java
public String readFile(String filename) {
String retString = null; try {
// initialize File and FileReader objects File file = new File(filename); FileReader fr = new FileReader(file);
// initialize character buffer long fLen = file.length(); char[] cBuf = new char[(int) fLen];
// read data from file int iRead = fr.read(cBuf, 0, (int) fLen);
// close file fr.close();
retString = new String(cBuf);
} catch (Exception ex) {
/* do nothing, but catch so it'll compile... */
} return retString;
}
The catch statement should contain statements that either attempt to fix the problem, notify the user that an exception has been raised and continue processing, or perform some cleanup and gracefully terminate the program. The following Java example contains three catch statements. The first of these will catch the FileNotFoundException that may be thrown by the FileReader constructor called within the try/catch block. The second catch statement will catch the IOException that may be thrown by the read method called within the try/catch block. The third catch statement will catch all other exceptions thrown within the try block. For all catch statements the user is notified that the exception has been thrown and the exception is rethrown to the block that called the readFile() method for further processing or possible termination of the program. Note that with Java it is usually good practice to use the getMessage() method of the exception class to provide more information to the user about the exception raised.
(good code)
Example Language: Java
public String readFile(String filename) throws FileNotFoundException, IOException, Exception {
String retString = null; try {
// initialize File and FileReader objects File file = new File(filename); FileReader fr = new FileReader(file);
// initialize character buffer long fLen = file.length(); char [] cBuf = new char[(int) fLen];
// read data from file int iRead = fr.read(cBuf, 0, (int) fLen);
// close file fr.close();
retString = new String(cBuf);
} catch (FileNotFoundException ex) {
System.err.println ("Error: FileNotFoundException opening the input file: " + filename ); System.err.println ("" + ex.getMessage() ); throw new FileNotFoundException(ex.getMessage());
} catch (IOException ex) {
System.err.println("Error: IOException reading the input file.\n" + ex.getMessage() ); throw new IOException(ex);
} catch (Exception ex) {
System.err.println("Error: Exception reading the input file.\n" + ex.getMessage() ); throw new Exception(ex);
A GPU data center manager detects an error due to a malformed request but does not act on it, leading to memory corruption.
Detection
Methods
Automated Static Analysis
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Effectiveness: High
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 CWE ID may be used to map to real-world vulnerabilities)
Reason:
Acceptable-Use
Rationale:
This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comments:
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.
Taxonomy
Mappings
Mapped Taxonomy Name
Node ID
Fit
Mapped Node Name
CLASP
Improper error handling
The CERT Oracle Secure Coding Standard for Java (2011)
[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 11: Failure to Handle Errors Correctly." Page 183. McGraw-Hill. 2010.
Description
This table 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.
