CVE-2023-24057 — MITM based Zip Slip in...

### Impact MITM can enable Zip-Slip. ### Vulnerability #### Vulnerability 1: `Scanner.java` There is no validation that the zip file being unpacked has entries that are not maliciously writing outside of the intended destination directory. https://github.com/hapifhir/org.hl7.fhir.core/blob/8c43e21094af971303131efd081503e5a112db4b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/Scanner.java#L335-L357 This zip archive is downloaded over HTTP instead of HTTPS, leaving it vulnerable to compromise in-flight. https://github.com/hapifhir/org.hl7.fhir.core/blob/8c43e21094af971303131efd081503e5a112db4b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/Scanner.java#L136 ##### Vulnerability 2: `TerminologyCacheManager.java` **Note:** While these links point to only one implementation, both implementations of `TerminologyCacheManager.java` are vulnerable to this as their code seems to be duplicated. - https://github.com/hapifhir/org.hl7.fhir.core/blob/f58b7acfb5e393cac52cc5bbb170bdb669c2880e/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/TerminologyCacheManager.java - https://github.com/hapifhir/org.hl7.fhir.core/blob/f58b7acfb5e393cac52cc5bbb170bdb669c2880e/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/terminologies/TerminologyCacheManager.java While there is validation in this bit of logic that attempts to validate that the zip file doesn't contain malicious entries that escape the destination directory, the guard is insufficient. https://github.com/hapifhir/org.hl7.fhir.core/blob/f58b7acfb5e393cac52cc5bbb170bdb669c2880e/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/TerminologyCacheManager.java#L97-L113 This is because the `Utilities.path(String... path)` method does not normalize the path, although it seems to be attempting to do so. https://github.com/hapifhir/org.hl7.fhir.core/blob/f58b7acfb5e393cac52cc5bbb170bdb669c2880e/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java#L617-L675 The normalization only occurs if the path element starts with a path traversal payload. As an example, calling `Utilities.path("/base", "/child/../test")` will return the string `"/base/child/../test"`. This guard logic can, thus, be easily bypassed: https://github.com/hapifhir/org.hl7.fhir.core/blob/f58b7acfb5e393cac52cc5bbb170bdb669c2880e/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/TerminologyCacheManager.java#L100-L104 Assuming an attacker can control the return value of `ze.getName()`, they can supply a value like `/anything/../../../../zipsip-protection-bypass.txt`. Similarly, an attacker can control the contents of the Zip file via a MITM attack as this logic is used with resources not downloaded over HTTPS. https://github.com/hapifhir/org.hl7.fhir.core/blob/f58b7acfb5e393cac52cc5bbb170bdb669c2880e/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/TerminologyCacheManager.java#L66-L73 ### Patches Unknown ### Workarounds Unknown ### References - https://snyk.io/research/zip-slip-vulnerability