Variant · Low-Medium

CWE-143: Improper Neutralization of Record Delimiters

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as record delimiters when they are sent to a dow...

CWE-143 · Variant Level ·2 CVEs ·4 Mitigations

Description

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as record 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.

Potential Impact

Integrity

Unexpected State

Mitigations & Prevention

General

Developers should anticipate that record 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.

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 relat

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 qu

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.

Real-World CVE Examples

CVE IDDescription
CVE-2004-1982Carriage returns in subject field allow adding new records to data file.
CVE-2001-0527Attacker inserts carriage returns and "|" field separator characters to add new user/privileges.

Taxonomy Mappings

  • PLOVER: — Record Delimiter
  • Software Fault Patterns: SFP24 — Tainted input to command

Frequently Asked Questions

What is CWE-143?

CWE-143 (Improper Neutralization of Record 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 record delimiters when they are sent to a dow...

How can CWE-143 be exploited?

Attackers can exploit CWE-143 (Improper Neutralization of Record Delimiters) to unexpected state. This weakness is typically introduced during the Implementation phase of software development.

How do I prevent CWE-143?

Key mitigations include: Developers should anticipate that record delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure onl

What is the severity of CWE-143?

CWE-143 is classified as a Variant-level weakness (Low-Medium abstraction). It has been observed in 2 real-world CVEs.