Uncontrolled Resource Consumption
The Security Team noticed that the termination condition of the for loop in the readExternal method is a controllable variable, which, if tampered with, may lead to CPU exhaustion. As a fix, we added an upper bound and termination condition in the read and write logic. We classify it as a "low-priority but useful improvement". SystemDS is a distributed system and needs to serialize/deserialize data but in many code paths (e.g., on Spark broadcast/shuffle or writing to sequence files) the byte stream is anyway protected by additional CRC fingerprints. In this particular case though, the number of decoders is upper-bounded by twice the number of columns, which means an attacker would need to modify two entries in the byte stream in a consistent manner. By adding these checks robustness was strictly improved with almost zero overhead. These code changes are available in versions higher than 2.2.1.
CWE-400 - Uncontrolled resource consumption
An uncontrolled resource allocation attack (also known as resource exhaustion attack) triggers unauthorized overconsumption of the limited resources in an application, such as memory, file system storage, database connection pool entries, and CPU. This may lead to denial of service for valid users and degradation of the application's functionality as well as that of the host operating system.