Description
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as macro symbols when they are sent to a downstream component.
Potential Impact
Integrity
Unexpected State
Mitigations & Prevention
Developers should anticipate that macro symbols 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
Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even
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 ID | Description |
|---|---|
| CVE-2002-0770 | Server trusts client to expand macros, allows macro characters to be expanded to trigger resultant information exposure. |
| CVE-2008-2018 | Attacker can obtain sensitive information from a database by using a comment containing a macro, which inserts the data during expansion. |
Related Weaknesses
Taxonomy Mappings
- PLOVER: — Macro Symbol
- Software Fault Patterns: SFP24 — Tainted input to command
Frequently Asked Questions
What is CWE-152?
CWE-152 (Improper Neutralization of Macro Symbols) 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 macro symbols when they are sent to a downstr...
How can CWE-152 be exploited?
Attackers can exploit CWE-152 (Improper Neutralization of Macro Symbols) to unexpected state. This weakness is typically introduced during the Implementation phase of software development.
How do I prevent CWE-152?
Key mitigations include: Developers should anticipate that macro symbols will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only va
What is the severity of CWE-152?
CWE-152 is classified as a Variant-level weakness (Low-Medium abstraction). It has been observed in 2 real-world CVEs.