CWE-341 Predictable from Observable State

A number or object is predictable based on observations that the attacker can make about the state of the system or network, such as time, process ID, etc.

• Other: Varies by Context — This weakness could be exploited by an attacker in a number of ways depending on the context. If a predictable number is used to generate IDs or keys that are used within protection mechanisms, then an attacker could gain unauthorized access to the system. If predictable filenames are used for storing sensitive information, then an attacker might gain access to the system and may be able to gain access to the information in the file.

• [Implementation] Increase the entropy used to seed a PRNG. • [Architecture and Design, Requirements] Use products or modules that conform to FIPS 140-2 [REF-267] to avoid obvious entropy problems. Consult FIPS 140-2 Annex C ("Approved Random Number Generators"). • [Implementation] Use a PRNG that periodically re-seeds itself using input from high-quality sources, such as hardware devices with high entropy. However, do not re-seed too frequently, or else the entropy source might block.

• Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

• CVE-2024-48445: Chain: e-commerce app relies on an easily-guessable timestamp (CWE-341) in a weak authentication algorithm (CWE-1390) • CVE-2002-0389: Mail server stores private mail messages with predictable filenames in a world-executable directory, which allows local users to read private mailing list archives. • CVE-2001-1141: PRNG allows attackers to use the output of small PRNG requests to determine the internal state information, which could be used by attackers to predict future pseudo-random numbers. • CVE-2000-0335: DNS resolver library uses predictable IDs, which allows a local attacker to spoof DNS query results. • CVE-2005-1636: MFV. predictable filename and insecure permissions allows file modification to execute SQL queries.