attack-surface.md

Attack Surface Analysis for iamkun/dayjs

Attack Surface: Unexpected Input Formats (Potentially High, Context-Dependent)

• Description: Attackers can provide malformed or unexpected date/time strings to dayjs parsing functions, aiming for unexpected behavior beyond simple parsing errors.
• How dayjs Contributes: dayjs's flexible parsing, while convenient, can be a weakness if the application doesn't strictly validate input before using dayjs. The potential for high severity comes from scenarios where the parsed (but still potentially attacker-influenced) date/time data is used in security-critical operations without further validation.
• Example: An application expects "YYYY-MM-DD" but receives a string containing special characters or an extremely long string. If the application then uses the partially parsed (and potentially manipulated) date components in a database query, file path, or other sensitive operation without additional checks, it could lead to more severe consequences than just a parsing error. This is a combination of dayjs's flexible parsing and the application's lack of subsequent validation.
• Impact: While typically Medium (DoS, unexpected behavior), the impact could be High if the parsed data is used in security-critical contexts without further validation. This could potentially lead to data corruption, unauthorized access, or other issues depending on the specific application logic. It's crucial to understand this is not a direct code execution vulnerability in dayjs itself, but a potential for misuse leading to higher-severity problems.
• Risk Severity: Potentially High (context-dependent; relies on how the application uses the parsed output).
• Mitigation Strategies:
  • Developer: Implement strict input validation before passing any data to dayjs. Use a whitelist of allowed formats. Always use the dayjs(string, format) constructor with an explicit format string for user-supplied input. Crucially, even after parsing with dayjs, validate the resulting date object and its components before using them in any security-sensitive operations. Treat the output of dayjs as potentially untrusted if the input was user-controlled. Employ a separate, robust date/time validation library for defense-in-depth.
  • User: (Not directly applicable).

Attack Surface: Prototype Pollution (Low Probability, but Potentially High Impact if Present)

• Description: Although unlikely in a well-maintained library like dayjs, a prototype pollution vulnerability could theoretically exist, allowing an attacker to modify the behavior of dayjs or other parts of the application. This is included because, if present, it would be a high-severity issue.
  • How dayjs Contributes: The vulnerability would stem from dayjs (or a closely related, officially supported component) improperly handling object merging or property assignment, allowing attacker-controlled properties to affect the global object prototype.
  • Example: An attacker provides a crafted object with a __proto__ property or other specially named properties, attempting to overwrite default dayjs methods or properties.
  • Impact: Potentially High. Successful prototype pollution could lead to arbitrary code execution, denial of service, or modification of application behavior in unpredictable ways.
  • Risk Severity: Low Probability, but High Impact if present.
  • Mitigation Strategies:
    • Developer: This is primarily a concern for the dayjs maintainers. However, application developers should:
      • Avoid passing user-controlled objects directly to dayjs methods without thorough sanitization and validation.
      • Be aware of any reports of prototype pollution vulnerabilities in dayjs and apply updates promptly.
      • Consider using security linters and static analysis tools that can detect potential prototype pollution vulnerabilities.
    • User: (Not directly applicable).