Modes Of Introduction
Implementation
Applicable Platforms
Language
Class: Not Language-Specific (Undetermined)
Common Consequences
Scope |
Impact |
Likelihood |
Integrity | Unexpected State | |
Observed Examples
References |
Description |
| "%" variable is expanded by wildcard function into disallowed commands. |
| Server trusts client to expand macros, allows macro characters to be expanded to trigger resultant information exposure. |
Potential Mitigations
Developers should anticipate that variable name delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
Phases : Implementation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
Phases : Implementation
While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments. The most conservative approach is to escape or filter all characters that do not pass an extremely strict allowlist (such as everything that is not alphanumeric or white space). If some special characters are still needed, such as white space, wrap each argument in quotes after the escaping/filtering step. Be careful of argument injection (CWE-88).
Phases : Implementation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
Vulnerability Mapping Notes
Justification : This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : 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.
Related Attack Patterns
CAPEC-ID |
Attack Pattern Name |
CAPEC-15 |
Command Delimiters An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or denylist input validation, as opposed to allowlist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or denylist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on. |
NotesNotes
Under-studied.
Submission
Name |
Organization |
Date |
Date release |
Version |
PLOVER |
|
2006-07-19 +00:00 |
2006-07-19 +00:00 |
Draft 3 |
Modifications
Name |
Organization |
Date |
Comment |
Eric Dalci |
Cigital |
2008-07-01 +00:00 |
updated Potential_Mitigations, Time_of_Introduction |
CWE Content Team |
MITRE |
2008-09-08 +00:00 |
updated Relationships, Taxonomy_Mappings |
CWE Content Team |
MITRE |
2008-10-14 +00:00 |
updated Description |
CWE Content Team |
MITRE |
2009-03-10 +00:00 |
updated Description, Name |
CWE Content Team |
MITRE |
2009-07-27 +00:00 |
updated Potential_Mitigations |
CWE Content Team |
MITRE |
2010-04-05 +00:00 |
updated Description, Name |
CWE Content Team |
MITRE |
2011-03-29 +00:00 |
updated Observed_Examples, Potential_Mitigations |
CWE Content Team |
MITRE |
2011-06-01 +00:00 |
updated Common_Consequences |
CWE Content Team |
MITRE |
2011-06-27 +00:00 |
updated Common_Consequences |
CWE Content Team |
MITRE |
2012-05-11 +00:00 |
updated Relationships |
CWE Content Team |
MITRE |
2012-10-30 +00:00 |
updated Potential_Mitigations |
CWE Content Team |
MITRE |
2014-07-30 +00:00 |
updated Relationships, Taxonomy_Mappings |
CWE Content Team |
MITRE |
2017-05-03 +00:00 |
updated Potential_Mitigations |
CWE Content Team |
MITRE |
2017-11-08 +00:00 |
updated Applicable_Platforms |
CWE Content Team |
MITRE |
2020-02-24 +00:00 |
updated Potential_Mitigations, Relationships |
CWE Content Team |
MITRE |
2020-06-25 +00:00 |
updated Potential_Mitigations |
CWE Content Team |
MITRE |
2023-01-31 +00:00 |
updated Description, Potential_Mitigations |
CWE Content Team |
MITRE |
2023-04-27 +00:00 |
updated Relationships |
CWE Content Team |
MITRE |
2023-06-29 +00:00 |
updated Mapping_Notes |