Описание
kurwov vulnerable to Denial of Service due to improper data sanitization
Summary
An unsafe sanitization of dataset contents on the MarkovData#getNext method used in Markov#generate and Markov#choose allows a maliciously crafted string on the dataset to throw and stop the function from running properly.
Details
If a string contains a forbidden substring (i.e. __proto__) followed by a space character, the second line will access a special property in MarkovData#finalData by removing the last character of the string, bypassing the dataset sanitization (as it is supposed to be already sanitized before this function is called).
data is then defined as the special function found in its prototype instead of an array.
On the last line, data is then indexed by a random number, which is supposed to return a string but returns undefined as it's a function. Calling endsWith then throws.
PoC
https://runkit.com/embed/m6uu40r5ja9b
Impact
Any dataset can be contaminated with the substring making it unable to properly generate anything in some cases.
Ссылки
- https://github.com/xiboon/kurwov/security/advisories/GHSA-hfrv-h3q8-9jpr
- https://nvd.nist.gov/vuln/detail/CVE-2024-34075
- https://github.com/xiboon/kurwov/commit/85d63e652594f121d6656177d7a3c0d823c976c9
- https://github.com/xiboon/kurwov/blob/0d58dfa42135ab40e830e92622857282f980ca89/src/MarkovData.ts#L38-L44
Пакеты
kurwov
>= 3.1.0, < 3.2.5
3.2.5
Связанные уязвимости
kurwov is a fast, dependency-free library for creating Markov Chains. An unsafe sanitization of dataset contents on the `MarkovData#getNext` method used in `Markov#generate` and `Markov#choose` allows a maliciously crafted string on the dataset to throw and stop the function from running properly. If a string contains a forbidden substring (i.e. `__proto__`) followed by a space character, the code will access a special property in `MarkovData#finalData` by removing the last character of the string, bypassing the dataset sanitization (as it is supposed to be already sanitized before this function is called). Any dataset can be contaminated with the substring making it unable to properly generate anything in some cases. This issue has been addressed in version 3.2.5 and all users are advised to upgrade. There are no known workarounds for this vulnerability.