GHSA-mc43-4fqr-c965 CVE-2024-34711
GeoServer has improper ENTITY_RESOLUTION_ALLOWLIST URI validation in XML Processing (SSRF)
High
Maven
- Severity
- 9.3 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 0.30%
- Chance of exploitation in the next 30 days. Higher than 22.55% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-20 Improper Input Validation
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
- CWE-611 Improper Restriction of XML External Entity Reference
- CWE-918 Server-Side Request Forgery (SSRF)
- Fix
- Available
- 2 packages have a fixed version
Description
Summary
An improper URI validation vulnerability exists that enables an unauthorized attacker to perform XML External Entities (XEE) attack, then send GET request to any HTTP server. Attacker can abuse this to scan internal networks and gain information about them then exploit further. Moreover, attacker can read limited .xsd file on system.
Details
By default, GeoServer use PreventLocalEntityResolver class from GeoTools to filter out malicious URIs in XML entities before resolving them. The URI must match the regex (?i)(jar:file|http|vfs)[^?#;]*\\.xsd. But the regex leaves a chance for attackers to request to any HTTP server or limited file.
Impact
An unauthenticated attacker can:
- Scan internal network to gain insight about it and exploit further.
- SSRF to endpoint ends with
.xsd. - Read limited
.xsdfile on system.
Mitigation
- Define the system property
ENTITY_RESOLUTION_ALLOWLISTto limit the supported external schema locaitons. - The built-in allow list covers the locations required for the operation of OGC web services:
www.w3.org,schemas.opengis.net,www.opengis.net,inspire.ec.europa.eu/schemas. - The user guide provides details on how to add additional locations (this is required for app-schema plugin where a schema is supplied to define an output format).
Resolution
- GeoServer 2.25.0 and greater default to the use of
ENTITY_RESOLUTION_ALLOWLISTand does not require you to provide a system property. - The use of
ENTITY_RESOLUTION_ALLOWLISTis still supported if you require additional schema locations to be supported beyond the built-in allow list. - GeoServer 2.25.1 change
ENTITY_RESOLUTION_ALLOWLISTno longer supports regular expressions
References
- External Entities Resolution (GeoServer User Guide)
Credits
- Le Mau Anh Phong from VNG Security Response Center & VNUHCM - University of Information Technology
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.geoserver.main:gs-main | < 2.25.0 |
2.25.0 |
| org.geoserver.web:gs-web-app | < 2.25.0 |
2.25.0 |
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.
org.geoserver.main:gs-main Maven → 2.25.0
- maven
<dependency><groupId>org.geoserver.main</groupId><artifactId>gs-main</artifactId><version>2.25.0</version></dependency>- gradle
implementation("org.geoserver.main:gs-main:2.25.0")
org.geoserver.web:gs-web-app Maven → 2.25.0
- maven
<dependency><groupId>org.geoserver.web</groupId><artifactId>gs-web-app</artifactId><version>2.25.0</version></dependency>- gradle
implementation("org.geoserver.web:gs-web-app:2.25.0")
Severity breakdown
CVSS 3.1 9.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Weakness
CWE-20: Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How to prevent it
- Architecture and Design: Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses. [REF-1109] [REF-1110] [REF-1111]
- Architecture and Design: Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Architecture and Design: 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. Even though client-side checks provide minimal benefits with respect to server-side security, they are still useful. First, they can support intrusion detection. If the server receives input that should have been rejected by the client, then it may be an indication of an attack. Second, client-side error-checking can provide helpful feedback to the user about the expectations for valid input. Third, there may be a reduction in server-side processing time for accidental input errors, although this is typically a small savings.
- Implementation: When your application combines data from multiple sources, perform the validation after the sources have been combined. The individual data elements may pass the validation step but violate the intended restrictions after they have been combined.
- Implementation: Be especially careful to validate all input when invoking code that crosses language boundaries, such as from an interpreted language to native code. This could create an unexpected interaction between the language boundaries. Ensure that you are not violating any of the expectations of the language with which you are interfacing. For example, even though Java may not be susceptible to buffer overflows, providing a large argument in a call to native code might trigger an overflow.
- Implementation: Directly convert your input type into the expected data type, such as using a conversion function that translates a string into a number. After converting to the expected data type, ensure that the input's values fall within the expected range of allowable values and that multi-field consistencies are maintained.
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180, CWE-181). Make sure that your application does not inadvertently decode the same input twice (CWE-174). Such errors could be used to bypass allowlist schemes by introducing dangerous inputs after they have been checked. Use libraries such as the OWASP ESAPI Canonicalization control. Consider performing repeated canonicalization until your input does not change any more. This will avoid double-decoding and similar scenarios, but it might inadvertently modify inputs that are allowed to contain properly-encoded dangerous content.
- Implementation: When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.
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-611: Improper Restriction of XML External Entity Reference
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
How to prevent it
- Implementation, System Configuration: Many XML parsers and validators can be configured to disable external entity expansion.
CWE-918: Server-Side Request Forgery (SSRF)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-fjf5-xgmq-5525 GeoServer is vulnerable to Unauthenticated XML External Entities (XXE) attack via WMS GetMap feature | Critical Known exploited | Also affects org.geoserver.web:gs-web-app |
| GHSA-6jj6-gm7p-fcvv Remote Code Execution (RCE) vulnerability in geoserver | Critical Known exploited | Also affects org.geoserver.web:gs-web-app |
| GHSA-wf6j-gr27-g7ch GeoServer has a Server-Side Template Injection (SSTI) vulnerability in processing FreeMarker templates | High | Also affects org.geoserver.web:gs-web-app |
| GHSA-x4r9-gmw3-hxww GeoServer has a Server-Side Request Forgery (SSRF) Vulnerability in its XML Entity Resolution | High | Also affects org.geoserver.web:gs-web-app |
| GHSA-7qmg-grcp-qf25 GeoServer has an arbitrary file write vulnerability in its Master Password Dump Page | High | Also affects org.geoserver.web:gs-web-app |
| GHSA-w66h-j855-qr72 GeoServer has a Reflected Cross-Site Scripting (XSS) vulnerability in its WMS GetFeatureInfo HTML format | Medium | Also affects org.geoserver.web:gs-web-app |
| GHSA-jj54-8f66-c5pc [XBOW-025-068] XML External Entity (XXE) Processing Vulnerability in GeoServer WFS Service | Critical | Also affects org.geoserver.web:gs-web-app |
| GHSA-gr67-pwcv-76gf GeoServer Infinite Loop Vulnerability in Jiffle process | High | Also affects org.geoserver.web:gs-web-app |
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