YAML Bomb

YAML Bomb

A YAML Bomb, also known as a resource exhaustion attack, is a type of cyberattack that exploits the way YAML (YAML Ain't Markup Language) parsers process data to consume excessive system resources, such as memory or CPU, leading to denial-of-service (DoS) conditions. YAML is a human-readable data serialization format used in configuration files and data exchange protocols, and YAML Bombs are designed to exploit the recursive nature of YAML structures to create extremely large files or data structures that overwhelm YAML parsers.

Operation

In a YAML Bomb attack, an attacker creates a specially crafted YAML file or data structure that contains recursive references or loops, causing the YAML parser to consume increasing amounts of memory or CPU resources as it attempts to process the data. This can lead to a DoS condition, where the system becomes unresponsive or crashes due to resource exhaustion.

Characteristics

Some key characteristics of YAML Bombs include:

• Small File Size: YAML Bombs can be relatively small in size but expand exponentially when parsed by a YAML parser, leading to resource exhaustion.
• Recursive Structures: YAML Bombs use recursive data structures, such as nested mappings or sequences, to create loops that cause parsers to consume resources indefinitely.
• Resource Exhaustion: YAML Bombs are designed to consume excessive amounts of memory or CPU resources, leading to DoS conditions on the target system.

Mitigation

To mitigate YAML Bomb attacks, organizations can take the following steps:

• Limit Resource Usage: Implement resource limits for YAML parsing operations to prevent excessive resource consumption.
• Use Safe Parsers: Use YAML parsers that include safeguards against YAML Bomb attacks, such as limiting recursion depth or enforcing size limits on parsed data.
• Regular Updates: Keep YAML parsers and related software up to date with the latest security patches and updates to protect against known vulnerabilities.
• Filter Untrusted Input: Filter and validate input data to ensure that YAML files or data structures do not contain malicious or malformed content.

Conclusion

YAML Bombs are a type of cyberattack that exploits the way YAML parsers process data to consume excessive system resources, leading to denial-of-service conditions. By understanding how YAML Bombs work and implementing appropriate mitigation measures, organizations can protect against this type of attack and ensure the security of their systems.