HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.0, when setting headers in HTTP requests, the internal HTTP client sends headers first to the host in the initial URL but also, if asked to follow redirects and a 30X HTTP response code is returned, to the host mentioned in URL in the Location: response header value. Sending the same set of headers to subsequent hosts is a problem as this header often contains privacy sensitive information or data that could allow others to impersonate the client's request. This issue has been patched in release 6.9.0. No known workarounds are available.
Impact
Zip Slip protections implemented in CVE-2023-24057 (GHSA-jqh6-9574-5x22) can be bypassed due a partial path traversal vulnerability.
This issue allows a malicious actor to potentially break out of the TerminologyCacheManager cache directory. The impact is limited to sibling directories.
To demonstrate the vulnerability, consider userControlled.getCanonicalPath().startsWith("/usr/out") will allow an attacker to access a directory with a name like /usr/outnot.
Why?
To demonstrate this vulnerability, consider "/usr/outnot".startsWith("/usr/out"). The check is bypassed although /outnot is not under the /out directory. It's important to understand that the terminating slash may be removed when using various String representations of the File object. For example, on Linux, println(new File("/var")) will print /var, but println(new File("/var", "/") will print /var/; however, println(new File("/var", "/").getCanonicalPath()) will print /var.
The Fix
Comparing paths with the java.nio.files.Path#startsWith will adequately protect againts this vulnerability.
For example: file.getCanonicalFile().toPath().startsWith(BASEDIRECTORY) or file.getCanonicalFile().toPath().startsWith(BASEDIRECTORYFILE.getCanonicalFile().toPath())
Other Examples
- CVE-2022-31159 - aws/aws-sdk-java - CVE-2022-23457 - ESAPI/esapi-java-legacy
Vulnerability
https://github.com/hapifhir/org.hl7.fhir.core/blob/b0daf666725fa14476d147522155af1e81922aac/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/terminologies/TerminologyCacheManager.java#L99-L105
While getAbsolutePath will return a normalized path, because the string path is not slash terminated, the guard can be bypassed to write the contents of the Zip file to a sibling directory of the cache directory.
Patches All org.hl7.fhir.core libraries should be updated to 5.6.106. - https://github.com/hapifhir/org.hl7.fhir.core/pull/1162
Workarounds Unknown
References https://snyk.io/research/zip-slip-vulnerability
HL7 (Health Level 7) FHIR Core Libraries before 5.6.92 allow attackers to extract files into arbitrary directories via directory traversal from a crafted ZIP or TGZ archive (for a prepackaged terminology cache, NPM package, or comparison archive).
XSS exists in the HAPI FHIR testpage overlay module of the HAPI FHIR library before 3.8.0. The attack involves unsanitized HTTP parameters being output in a form page, allowing attackers to leak cookies and other sensitive information from ca/uhn/fhir/to/BaseController.java via a specially crafted URL. (This module is not generally used in production systems so the attack surface is expected to be low, but affected systems are recommended to upgrade immediately.)
Users of the HAPI FHIR Testpage Overlay 5.0.0 and below can use a specially crafted URL to exploit an XSS vulnerability in this module, allowing arbitrary JavaScript to be executed in the user's browser. The impact of this vulnerability is believed to be low, as this module is intended for testing and not believed to be widely used for any production purposes.
JPA Server in HAPI FHIR before 5.4.0 allows a user to deny service (e.g., disable access to the database after the attack stops) via history requests. This occurs because of a SELECT COUNT statement that requires a full index scan, with an accompanying large amount of server resources if there are many simultaneous history requests.