GHSA-5pv8-ppvj-4h68 BIT-symfony-2021-21424 CVE-2021-21424
Prevent user enumeration using Guard or the new Authenticator-based Security
Medium
Packagist
- Severity
- 5.3 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 1.64%
- Chance of exploitation in the next 30 days. Higher than 76.44% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
- CWE-203 Observable Discrepancy
- Fix
- Available
- 7 packages have a fixed version
Description
Description
The ability to enumerate users was possible without relevant permissions due to different exception messages depending on whether the user existed or not. It was also possible to enumerate users by using a timing attack, by comparing time elapsed when authenticating an existing user and authenticating a non-existing user.
Resolution
We now ensure that 403s are returned whether the user exists or not if the password is invalid or if the user does not exist.
The patch for this issue is available here for branch 3.4.
Credits
I would like to thank James Isaac and Mathias Brodala for reporting the issue and Robin Chalas for fixing the issue.
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| lexik/jwt-authentication-bundle | >= 2.0.0, < 2.10.7 |
2.10.7 |
| lexik/jwt-authentication-bundle | >= 2.11.0, < 2.11.3 |
2.11.3 |
| symfony/maker-bundle | >= 1.27.0, < 1.29.2 |
1.29.2 |
| symfony/maker-bundle | >= 1.30.0, < 1.31.1 |
1.31.1 |
| symfony/security | >= 5.0.0, < 5.2.8 |
5.2.8 |
| symfony/security | >= 2.8.0, < 3.4.49 |
3.4.49 |
| symfony/security | >= 4.0.0, < 4.4.24 |
4.4.24 |
| symfony/security-core | >= 2.8.0, < 3.4.48 |
3.4.48 |
| symfony/security-core | >= 4.0.0, < 4.4.23 |
4.4.23 |
| symfony/security-core | >= 5.0.0, < 5.2.8 |
5.2.8 |
| symfony/security-guard | >= 2.8.0, < 3.4.48 |
3.4.48 |
| symfony/security-guard | >= 4.0.0, < 4.4.23 |
4.4.23 |
| symfony/security-guard | >= 5.0.0, < 5.2.8 |
5.2.8 |
| symfony/security-http | >= 5.1.0, < 5.2.8 |
5.2.8 |
| symfony/symfony | >= 2.8.0, < 3.4.49 |
3.4.49 |
| symfony/symfony | >= 4.0.0, < 4.4.24 |
4.4.24 |
| symfony/symfony | >= 5.0.0, < 5.2.9 |
5.2.9 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
lexik/jwt-authentication-bundle Packagist → 2.10.7
- composer
composer require lexik/jwt-authentication-bundle:^2.10.7
symfony/maker-bundle Packagist → 1.29.2
- composer
composer require symfony/maker-bundle:^1.29.2
symfony/security Packagist → 5.2.8
- composer
composer require symfony/security:^5.2.8
symfony/security-core Packagist → 3.4.48
- composer
composer require symfony/security-core:^3.4.48
symfony/security-guard Packagist → 3.4.48
- composer
composer require symfony/security-guard:^3.4.48
symfony/security-http Packagist → 5.2.8
- composer
composer require symfony/security-http:^5.2.8
symfony/symfony Packagist → 3.4.49
- composer
composer require symfony/symfony:^3.4.49
Severity breakdown
CVSS 3.1 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
How to prevent it
- Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
CWE-203: Observable Discrepancy
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.
How to prevent it
- Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
- Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
References
Advisories
Packages
Other links
- github.com/symfony/symfony/security/advisories/GHSA-5pv8-ppvj-4h68
- github.com/symfony/symfony/commit/2a581d22cc621b33d5464ed65c4bc2057f72f011
- symfony.com/cve-2021-21424
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VRUS2…
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UC7BN…
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RH7TM…
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KENRN…
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VRU…
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UC7…
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RH7…
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KEN…
- lists.debian.org/debian-lts-announce/2023/07/msg00014.html
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-202…
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security/CVE-20…
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security-http/C…
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security-guard/…
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/maker-bundle/CV…
- github.com/FriendsOfPHP/security-advisories/blob/master/lexik/jwt-authenticatio…
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-2v3c-qxhr-7vpv Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process | High | Also affects symfony/symfony |
| GHSA-r925-mgvr-h9cc Symfony: ReDoS in HeaderUtils::split() Reachable Through the Cache-Control Request Header | High | Also affects symfony/symfony |
| GHSA-h5x3-xfc9-m39h Symfony: UrlGenerator Dot-Segment Encoding Skips Every Other Chained `../` or `./` → Generated URL Collapses Off-Route Under RFC 3986 Normalization | Medium | Also affects symfony/symfony |
| GHSA-v3wm-qf9p-c549 Symfony: HtmlSanitizer URL Parser Deny Gates Underinclusive: Percent-Encoded BiDi Marks and Unicode Whitespace Bypass Visual-Spoofing Defense | Medium | Also affects symfony/symfony |
| GHSA-rrj9-5q2j-4gvr Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade | Medium | Also affects symfony/symfony |
| GHSA-38cx-cq6f-5755 Symfony: IpUtils::PRIVATE_SUBNETS Omits IPv6 Transition Forms (6to4, NAT64, Teredo, IPv4-compatible): SSRF Bypass in NoPrivateNetworkHttpClient | High | Also affects symfony/symfony |
| GHSA-6h46-9jf5-q59x Symfony: Security Firewall Bypass via failure_forward Subrequest: Unauthenticated Access to access_control-Protected GET Routes | High | Also affects symfony/security-http |
| GHSA-x5qj-865h-mgvm Symfony: HtmlSanitizer UrlAttributeSanitizer Misses URL Attributes | Medium | Also affects symfony/symfony |
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