Apache Solr: Unrestricted Upload of File with Dangerous Type
CVE-2023-50386 is a high-severity unrestricted upload of file with dangerous type vulnerability in Apache Solr from Apache, with a CVSS 3.1 base score of 8.8 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. The record lists version 9.4.1 as the first without the flaw, so updating Apache Solr to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 83.7% chance of exploitation within 30 days, which is in the top 0.31% of all scored CVEs.
Exploitation in the next 30 days is more likely than not, according to EPSS.
What to do
- Update Apache Solr to 9.4.1 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Solr | 6.0.0 through 8.11.2; 9.0.0 up to, but not including, 9.4.1 | 9.4.1 |
| Apache | solr | 6.0.0 | 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
- LowNo special conditions are needed; the attack works reliably.
- 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:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
Official description
Improper Control of Dynamically-Managed Code Resources, Unrestricted Upload of File with Dangerous Type, Inclusion of Functionality from Untrusted Control Sphere vulnerability in Apache Solr.This issue affects Apache Solr: from 6.0.0 through 8.11.2, from 9.0.0 before 9.4.1. In the affected versions, Solr ConfigSets accepted Java jar and class files to be uploaded through the ConfigSets API. When backing up Solr Collections, these configSet files would be saved to disk when using the LocalFileSystemRepository (the default for backups). If the backup was saved to a directory that Solr uses in its ClassPath/ClassLoaders, then the jar and class files would be available to use with any ConfigSet, trusted or untrusted. When Solr is run in a secure way (Authorization enabled), as is strongly suggested, this vulnerability is limited to extending the Backup permissions with the ability to add libraries. Users are recommended to upgrade to version 8.11.3 or 9.4.1, which fix the issue. In these versions, the following protections have been added: * Users are no longer able to upload files to a configSet that could be executed via a Java ClassLoader. * The Backup API restricts saving backups to directories that are used in the ClassLoader.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Unrestricted Upload of File with Dangerous Type
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
How developers prevent this class of flaw
- Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
- Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically.
More Unrestricted Upload of File with Dangerous Type vulnerabilities (CWE-434)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
Other references
- openwall.com/lists/oss-security/2024/02/09/1Mailing List
Other vulnerabilities in Apache Solr
- 9.8 Critical severity
- 7.1 High severity
- 8.2 High severity
- 8.1 High severity
- 9.8 Critical severity
- 7.5 High severity
Recent Unrestricted Upload of File with Dangerous Type vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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