rubygems.org: Incorrect Authorization
CVE-2022-29176 is a high-severity incorrect authorization vulnerability in rubygems.org from Rubygems, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 1.94% chance of exploitation within 30 days, higher than 80% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of rubygems.org you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Rubygems | rubygems.org | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.9 | Critical | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 2.0 | 6.0 | Medium | NVD |
Official description
Rubygems is a package registry used to supply software for the Ruby language ecosystem. Due to a bug in the yank action, it was possible for any RubyGems.org user to remove and replace certain gems even if that user was not authorized to do so. To be vulnerable, a gem needed: one or more dashes in its name creation within 30 days OR no updates for over 100 days At present, we believe this vulnerability has not been exploited. RubyGems.org sends an email to all gem owners when a gem version is published or yanked. We have not received any support emails from gem owners indicating that their gem has been yanked without authorization. An audit of gem changes for the last 18 months did not find any examples of this vulnerability being used in a malicious way. A deeper audit for any possible use of this exploit is ongoing, and we will update this advisory once it is complete. Using Bundler in --frozen or --deployment mode in CI and during deploys, as the Bundler team has always recommended, will guarantee that your application does not silently switch to versions created using this exploit. To audit your application history for possible past exploits, review your Gemfile.lock and look for gems whose platform changed when the version number did not change. For example, gemname-3.1.2 updating to gemname-3.1.2-java could indicate a possible abuse of this vulnerability. RubyGems.org has been patched and is no longer vulnerable to this issue as of the 5th of May 2022.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How developers prevent this class of flaw
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework and the OWASP ESAPI Access Control feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/rubygems/rubygems.org/security/advisories/GHSA-hccv-rwq6-vh79Mitigation, Third Party Advisory
Third-party and government advisories
- hackerone.com/bugs?subject=rubygems&report_id=1559856Permissions Required, Third Party Advisory
- security.netapp.com/advisory/ntap-20220616-0002/Third Party Advisory
Other vulnerabilities in rubygems.org
- 9.8 Critical severity
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
Recent Incorrect Authorization vulnerabilities
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
- 9.8 Critical severity
- 10.0 Critical severity
- 7.5 High severity
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