Ruby on Rails Directory Traversal
CVE-2016-0752 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in Rails from Rubyonrails, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 3.2.22.1, 4.1.14.1, 4.2.5.1 as the first without the flaw, so updating Rails to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on March 25, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Rails to 3.2.22.1 or 4.1.14.1 or 4.2.5.1, whichever matches your release line, or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Rubyonrails | Rails | before 3.2.22.1; 4.0.0 up to, but not including, 4.1.14.1; 4.2.0 up to, but not including, 4.2.5.1; 5.0.0 | 3.2.22.1, 4.1.14.1, 4.2.5.1 |
| openSUSE | Leap | 42.1 | Not stated |
| openSUSE | Opensuse | 13.2 | Not stated |
| SUSE | Linux Enterprise Module For Containers | 12 | Not stated |
| Debian | Debian Linux | 8.0 | Not stated |
| Red Hat | Software Collections | 1.0 | Not stated |
Version data comes from NVD's product matching. 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
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 3.1 | 7.5 | High | CISA (ADP) |
| CVSS 2.0 | 5.0 | Medium | NVD |
Official description
Directory traversal vulnerability in Action View in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 allows remote attackers to read arbitrary files by leveraging an application's unrestricted use of the render method and providing a .. (dot dot) in a pathname.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- lists.opensuse.org/opensuse-security-announce/2016-04/msg00053.htmlMailing List, Third Party Advisory
- lists.opensuse.org/opensuse-updates/2016-02/msg00034.htmlMailing List, Third Party Advisory
- lists.opensuse.org/opensuse-updates/2016-02/msg00043.htmlMailing List, Third Party Advisory
- rhn.redhat.com/errata/RHSA-2016-0296.htmlThird Party Advisory
- debian.org/security/2016/dsa-3464Mailing List, Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-0752US Government Resource
Technical write-ups (may include proof of concept)
- openwall.com/lists/oss-security/2016/01/25/13Exploit, Mailing List
- exploit-db.com/exploits/40561/Exploit, Third Party Advisory, VDB Entry
Other references
- lists.fedoraproject.org/pipermail/package-announce/2016-February/178044.htmlPermissions Required
- lists.fedoraproject.org/pipermail/package-announce/2016-February/178069.htmlPermissions Required
Other vulnerabilities in Rails
- 9.1 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 9.1 Critical severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 3.5 Low severity
IBM InfoSphere BigInsights Invalid Input Exploited
- 7.5 High severity
Ruby on Rails Directory Traversal Exploited
Spotted an error? Tell us.