Read Time:10 Second
Description
The software does not handle or incorrectly handles inputs that are related to complex structures.
Modes of Introduction:
Related Weaknesses
Consequences
Integrity: Unexpected State
Category Archives: CWE
CWE-238 – Improper Handling of Incomplete Structural Elements
Read Time:12 Second
Description
The software does not handle or incorrectly handles when a particular structural element is not completely specified.
Modes of Introduction:
– Architecture and Design
Related Weaknesses
Consequences
Integrity: Unexpected State
Potential Mitigations
CVE References
CWE-200 – Exposure of Sensitive Information to an Unauthorized Actor
Read Time:1 Minute, 47 Second
Description
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
Modes of Introduction:
– Architecture and Design
Likelihood of Exploit: High
Related Weaknesses
Consequences
Confidentiality: Read Application Data
Potential Mitigations
Phase: Architecture and Design
Description:
CVE References
- CVE-2001-1483
- Enumeration of valid usernames based on inconsistent responses
- CVE-2001-1528
- Account number enumeration via inconsistent responses.
- CVE-2004-2150
- User enumeration via discrepancies in error messages.
- CVE-2005-1205
- Telnet protocol allows servers to obtain sensitive environment information from clients.
- CVE-2002-1725
- Script calls phpinfo(), revealing system configuration to web user
- CVE-2002-0515
- Product sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.
- CVE-2004-0778
- Version control system allows remote attackers to determine the existence of arbitrary files and directories via the -X command for an alternate history file, which causes different error messages to be returned.
- CVE-2000-1117
- Virtual machine allows malicious web site operators to determine the existence of files on the client by measuring delays in the execution of the getSystemResource method.
- CVE-2003-0190
- Product immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.
- CVE-2008-2049
- POP3 server reveals a password in an error message after multiple APOP commands are sent. Might be resultant from another weakness.
- CVE-2007-5172
- Program reveals password in error message if attacker can trigger certain database errors.
- CVE-2008-4638
- Composite: application running with high privileges (CWE-250) allows user to specify a restricted file to process, which generates a parsing error that leaks the contents of the file (CWE-209).
- CVE-2007-1409
- Direct request to library file in web application triggers pathname leak in error message.
- CVE-2005-0603
- Malformed regexp syntax leads to information exposure in error message.
- CVE-2004-2268
- Password exposed in debug information.
- CVE-2003-1078
- FTP client with debug option enabled shows password to the screen.
CWE-201 – Insertion of Sensitive Information Into Sent Data
Read Time:1 Minute, 1 Second
Description
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.
Sensitive information could include data that is sensitive in and of itself (such as credentials or private messages), or otherwise useful in the further exploitation of the system (such as internal file system structure).
Modes of Introduction:
– Implementation
Related Weaknesses
Consequences
Confidentiality: Read Files or Directories, Read Memory, Read Application Data
Sensitive data may be exposed to attackers.
Potential Mitigations
Phase: Requirements
Description:
Specify which data in the software should be regarded as sensitive. Consider which types of users should have access to which types of data.
Phase: Implementation
Description:
Ensure that any possibly sensitive data specified in the requirements is verified with designers to ensure that it is either a calculated risk or mitigated elsewhere. Any information that is not necessary to the functionality should be removed in order to lower both the overhead and the possibility of security sensitive data being sent.
Phase: System Configuration
Description:
Setup default error messages so that unexpected errors do not disclose sensitive information.
Phase: Architecture and Design
Description:
CVE References
CWE-202 – Exposure of Sensitive Information Through Data Queries
Read Time:41 Second
Description
When trying to keep information confidential, an attacker can often infer some of the information by using statistics.
In situations where data should not be tied to individual users, but a large number of users should be able to make queries that “scrub” the identity of users, it may be possible to get information about a user — e.g., by specifying search terms that are known to be unique to that user.
Modes of Introduction:
– Architecture and Design
Likelihood of Exploit: Medium
Related Weaknesses
Consequences
Confidentiality: Read Files or Directories, Read Application Data
Sensitive information may possibly be leaked through data queries accidentally.
Potential Mitigations
Phase: Architecture and Design
Description:
This is a complex topic. See the book Translucent Databases for a good discussion of best practices.
CVE References
CWE-203 – Observable Discrepancy
Read Time:3 Minute, 36 Second
Description
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not.
Discrepancies can take many forms, and variations may be detectable in timing, control flow, communications such as replies or requests, or general behavior. These discrepancies can reveal information about the product’s operation or internal state to an unauthorized actor. In some cases, discrepancies can be used by attackers to form a side channel.
Modes of Introduction:
– Architecture and Design
Related Weaknesses
Consequences
Confidentiality, Access Control: Read Application Data, Bypass Protection Mechanism
An attacker can gain access to sensitive information about the system, including authentication information that may allow an attacker to gain access to the system.
Confidentiality: Read Application Data
When cryptographic primitives are vulnerable to side-channel-attacks, this could be used to reveal unencrypted plaintext in the worst case.
Potential Mitigations
Phase: Architecture and Design
Description:
Phase: Implementation
Description:
CVE References
- CVE-2020-8695
- Observable discrepancy in the RAPL interface for some Intel processors allows information disclosure.
- CVE-2002-2094
- This, and others, use “..” attacks and monitor error responses, so there is overlap with directory traversal.
- CVE-2001-1483
- Enumeration of valid usernames based on inconsistent responses
- CVE-2001-1528
- Account number enumeration via inconsistent responses.
- CVE-2004-2150
- User enumeration via discrepancies in error messages.
- CVE-2005-1650
- User enumeration via discrepancies in error messages.
- CVE-2004-0294
- Bulletin Board displays different error messages when a user exists or not, which makes it easier for remote attackers to identify valid users and conduct a brute force password guessing attack.
- CVE-2004-0243
- Operating System, when direct remote login is disabled, displays a different message if the password is correct, which allows remote attackers to guess the password via brute force methods.
- CVE-2002-0514
- Product allows remote attackers to determine if a port is being filtered because the response packet TTL is different than the default TTL.
- CVE-2002-0515
- Product sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.
- CVE-2002-0208
- Product modifies TCP/IP stack and ICMP error messages in unusual ways that show the product is in use.
- CVE-2004-2252
- Behavioral infoleak by responding to SYN-FIN packets.
- CVE-2001-1387
- Product may generate different responses than specified by the administrator, possibly leading to an information leak.
- CVE-2004-0778
- Version control system allows remote attackers to determine the existence of arbitrary files and directories via the -X command for an alternate history file, which causes different error messages to be returned.
- CVE-2004-1428
- FTP server generates an error message if the user name does not exist instead of prompting for a password, which allows remote attackers to determine valid usernames.
- CVE-2003-0078
- SSL implementation does not perform a MAC computation if an incorrect block cipher padding is used, which causes an information leak (timing discrepancy) that may make it easier to launch cryptographic attacks that rely on distinguishing between padding and MAC verification errors, possibly leading to extraction of the original plaintext, aka the “Vaudenay timing attack.”
- CVE-2000-1117
- Virtual machine allows malicious web site operators to determine the existence of files on the client by measuring delays in the execution of the getSystemResource method.
- CVE-2003-0637
- Product uses a shorter timeout for a non-existent user than a valid user, which makes it easier for remote attackers to guess usernames and conduct brute force password guessing.
- CVE-2003-0190
- Product immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.
- CVE-2004-1602
- FTP server responds in a different amount of time when a given username exists, which allows remote attackers to identify valid usernames by timing the server response.
- CVE-2005-0918
- Browser allows remote attackers to determine the existence of arbitrary files by setting the src property to the target filename and using Javascript to determine if the web page immediately stops loading, which indicates whether the file exists or not.
CWE-204 – Observable Response Discrepancy
Read Time:1 Minute, 49 Second
Description
The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.
This issue frequently occurs during authentication, where a difference in failed-login messages could allow an attacker to determine if the username is valid or not. These exposures can be inadvertent (bug) or intentional (design).
Modes of Introduction:
– Architecture and Design
Related Weaknesses
Consequences
Confidentiality, Access Control: Read Application Data, Bypass Protection Mechanism
Potential Mitigations
Phase: Architecture and Design
Description:
Phase: Implementation
Description:
CVE References
- CVE-2002-2094
- This, and others, use “..” attacks and monitor error responses, so there is overlap with directory traversal.
- CVE-2001-1483
- Enumeration of valid usernames based on inconsistent responses
- CVE-2001-1528
- Account number enumeration via inconsistent responses.
- CVE-2004-2150
- User enumeration via discrepancies in error messages.
- CVE-2005-1650
- User enumeration via discrepancies in error messages.
- CVE-2004-0294
- Bulletin Board displays different error messages when a user exists or not, which makes it easier for remote attackers to identify valid users and conduct a brute force password guessing attack.
- CVE-2004-0243
- Operating System, when direct remote login is disabled, displays a different message if the password is correct, which allows remote attackers to guess the password via brute force methods.
- CVE-2002-0514
- Product allows remote attackers to determine if a port is being filtered because the response packet TTL is different than the default TTL.
- CVE-2002-0515
- Product sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.
- CVE-2001-1387
- Product may generate different responses than specified by the administrator, possibly leading to an information leak.
- CVE-2004-0778
- Version control system allows remote attackers to determine the existence of arbitrary files and directories via the -X command for an alternate history file, which causes different error messages to be returned.
- CVE-2004-1428
- FTP server generates an error message if the user name does not exist instead of prompting for a password, which allows remote attackers to determine valid usernames.
CWE-205 – Observable Behavioral Discrepancy
Read Time:42 Second
Description
The product’s behaviors indicate important differences that may be observed by unauthorized actors in a way that reveals (1) its internal state or decision process, or (2) differences from other products with equivalent functionality.
Ideally, a product should provide as little information about its internal operations as possible. Otherwise, attackers could use knowledge of these internal operations to simplify or optimize their attack. In some cases, behavioral discrepancies can be used by attackers to form a side channel.
Modes of Introduction:
– Architecture and Design
Related Weaknesses
Consequences
Confidentiality, Access Control: Read Application Data, Bypass Protection Mechanism
Potential Mitigations
CVE References
- CVE-2002-0208
- Product modifies TCP/IP stack and ICMP error messages in unusual ways that show the product is in use.
- CVE-2004-2252
- Behavioral infoleak by responding to SYN-FIN packets.
CWE-206 – Observable Internal Behavioral Discrepancy
Read Time:1 Minute, 33 Second
Description
The product performs multiple behaviors that are combined to produce a single result, but the individual behaviors are observable separately in a way that allows attackers to reveal internal state or internal decision points.
Ideally, a product should provide as little information as possible to an attacker. Any hints that the attacker may be making progress can then be used to simplify or optimize the attack. For example, in a login procedure that requires a username and password, ultimately there is only one decision: success or failure. However, internally, two separate actions are performed: determining if the username exists, and checking if the password is correct. If the product behaves differently based on whether the username exists or not, then the attacker only needs to concentrate on the password.
Modes of Introduction:
– Architecture and Design
Related Weaknesses
Consequences
Confidentiality, Access Control: Read Application Data, Bypass Protection Mechanism
Potential Mitigations
Phase:
Description:
Setup generic response pages for error conditions. The error page should not disclose information about the success or failure of a sensitive operation. For instance, the login page should not confirm that the login is correct and the password incorrect. The attacker who tries random account name may be able to guess some of them. Confirming that the account exists would make the login page more susceptible to brute force attack.
CVE References
- CVE-2002-2031
- File existence via infoleak monitoring whether “onerror” handler fires or not.
- CVE-2005-2025
- Valid groupname enumeration via behavioral infoleak (sends response if valid, doesn’t respond if not).
- CVE-2001-1497
- Behavioral infoleak in GUI allows attackers to distinguish between alphanumeric and non-alphanumeric characters in a password, thus reducing the search space.
- CVE-2003-0190
- Product immediately sends an error message when user does not exist instead of waiting until the password is provided, allowing username enumeration.
CWE-207 – Observable Behavioral Discrepancy With Equivalent Products
Read Time:1 Minute, 14 Second
Description
The product operates in an environment in which its existence or specific identity should not be known, but it behaves differently than other products with equivalent functionality, in a way that is observable to an attacker.
For many kinds of products, multiple products may be available that perform the same functionality, such as a web server, network interface, or intrusion detection system. Attackers often perform “fingerprinting,” which uses discrepancies in order to identify which specific product is in use. Once the specific product has been identified, the attacks can be made more customized and efficient. Often, an organization might intentionally allow the specific product to be identifiable. However, in some environments, the ability to identify a distinct product is unacceptable, and it is expected that every product would behave in exactly the same way. In these more restricted environments, a behavioral difference might pose an unacceptable risk if it makes it easier to identify the product’s vendor, model, configuration, version, etc.
Modes of Introduction:
– Architecture and Design
Related Weaknesses
Consequences
Confidentiality, Access Control: Read Application Data, Bypass Protection Mechanism
Potential Mitigations
CVE References
- CVE-2002-0208
- Product modifies TCP/IP stack and ICMP error messages in unusual ways that show the product is in use.
- CVE-2004-2252
- Behavioral infoleak by responding to SYN-FIN packets.
- CVE-2000-1142
- Honeypot generates an error with a “pwd” command in a particular directory, allowing attacker to know they are in a honeypot system.