CVE-2016-1000236
Timing attack vulnerability in cookie-signature (npm)
What is CVE-2016-1000236 About?
The `cookie-signature` package is vulnerable to timing attacks due to the use of a fail-early comparison for secrets instead of a constant-time comparison. This vulnerability significantly reduces the entropy of secrets, making them easier to guess. Exploitation requires careful timing measurements and favorable network conditions.
Affected Software
Technical Details
The cookie-signature package, in affected versions, implements secret comparison using a fail-early mechanism, meaning the comparison stops as soon as a mismatch is found between characters. This behavior leaks information about the correctness of each character guess through subtle timing differences. If an attacker can accurately measure the time taken for comparison, they can deduce the correct secret character by character. A correct character match will typically take slightly longer to compare than an incorrect one (due to the comparison proceeding to the next character), especially under stable network conditions. This effectively transforms an exponential guessing problem (charset^length) into a linear one (charset*length), severely compromising the security of the secret.
What is the Impact of CVE-2016-1000236?
Successful exploitation may allow attackers to guess secret keys more efficiently, potentially bypassing authentication mechanisms or forging signed cookies, leading to session hijacking or unauthorized access.
What is the Exploitability of CVE-2016-1000236?
Exploitation of this timing attack vulnerability is of high complexity. It does not require authentication or specific privileges, but it relies on an attacker being able to precisely measure response times from the server. The attack is primarily remote, requiring the attacker to send numerous requests with varying guessed secret characters and accurately measure the server's response time to deduce the secret. Prerequisites include stable network conditions to minimize noise in timing measurements. Special conditions involve the attacker having direct network access to the target and a consistent network path. Risk factors include the server being publicly accessible and the attacker's ability to send a large volume of requests and analyze timing differences without interference.
What are the Known Public Exploits?
| PoC Author | Link | Commentary |
|---|---|---|
| No known exploits | ||
What are the Available Fixes for CVE-2016-1000236?
Available Upgrade Options
- cookie-signature
- <1.0.4 → Upgrade to 1.0.4
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Book a demoAdditional Resources
- https://www.npmjs.com/advisories/134
- https://nvd.nist.gov/vuln/detail/CVE-2016-1000236
- https://security-tracker.debian.org/tracker/CVE-2016-1000236
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2016-1000236
- https://bugzilla.redhat.com/show_bug.cgi?id=1371409
- https://github.com/tj/node-cookie-signature/commit/4cc5e21e7f59a4ea0b51cd5e9634772d48fab590
- https://www.mail-archive.com/secure-testing-team@lists.alioth.debian.org/msg06583.html
- https://github.com/tj/node-cookie-signature/commit/2c4df6b6cee540f30876198cd0b5bebf28528c07
- https://github.com/tj/node-cookie-signature
- https://www.mail-archive.com/secure-testing-team%40lists.alioth.debian.org/msg06583.html
What are Similar Vulnerabilities to CVE-2016-1000236?
Similar Vulnerabilities: CVE-2019-15822 , CVE-2020-8199 , CVE-2020-8200 , CVE-2020-8201 , CVE-2020-17049
