Description
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as section delimiters when they are sent to a downstream component.
As data is parsed, an injected/absent/malformed delimiter may cause the process to take unexpected actions. One example of a section delimiter is the boundary string in a multipart MIME message. In many cases, doubled line delimiters can serve as a section delimiter.
Potential Impact
Integrity
Unexpected State
Mitigations & Prevention
Developers should anticipate that section 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.
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 relat
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 qu
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.
Related Weaknesses
Taxonomy Mappings
- PLOVER: — Section Delimiter
- Software Fault Patterns: SFP24 — Tainted input to command
Frequently Asked Questions
What is CWE-145?
CWE-145 (Improper Neutralization of Section Delimiters) is a software weakness identified by MITRE's Common Weakness Enumeration. It is classified as a Variant-level weakness. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as section delimiters when they are sent to a do...
How can CWE-145 be exploited?
Attackers can exploit CWE-145 (Improper Neutralization of Section Delimiters) to unexpected state. This weakness is typically introduced during the Implementation phase of software development.
How do I prevent CWE-145?
Key mitigations include: Developers should anticipate that section delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure on
What is the severity of CWE-145?
CWE-145 is classified as a Variant-level weakness (Low-Medium abstraction). Its actual severity depends on the specific context and how the weakness manifests in your application.