Headline
CVE-2023-23926: [AJmycukR] Fix for apoc.import.graphml by Lojjs · Pull Request #310 · neo4j/apoc
APOC (Awesome Procedures on Cypher) is an add-on library for Neo4j. An XML External Entity (XXE) vulnerability found in the apoc.import.graphml procedure of APOC core plugin prior to version 5.5.0 in Neo4j graph database. XML External Entity (XXE) injection occurs when the XML parser allows external entities to be resolved. The XML parser used by the apoc.import.graphml procedure was not configured in a secure way and therefore allowed this. External entities can be used to read local files, send HTTP requests, and perform denial-of-service attacks on the application. Abusing the XXE vulnerability enabled assessors to read local files remotely. Although with the level of privileges assessors had this was limited to one-line files. With the ability to write to the database, any file could have been read. Additionally, assessors noted, with local testing, the server could be crashed by passing in improperly formatted XML. The minimum version containing a patch for this vulnerability is 5.5.0. Those who cannot upgrade the library can control the allowlist of the procedures that can be used in your system.
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I think that different XML parsers in Java have different behaviour and work well for different things. The XMLInputFactory is however used in another place IIRC.
We could have our own XMLParserFactory which returns an XMLEventReader with sensible defaults. I leave it up to you whether you’d like to explore that. However, neither do I see this procedure staying in APOC Core in the long term, nor do I anticipate many code changes in this procedure between now and 2025 when 4.4 goes out of support.
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### Impact A XML External Entity (XXE) vulnerability found in the apoc.import.graphml procedure of APOC core plugin in Neo4j graph database. XML External Entity (XXE) injection occurs when the XML parser allows external entities to be resolved. The XML parser used by the apoc.import.graphml procedure was not configured in a secure way and therefore allowed this. External entities can be used to read local files, send HTTP requests, and perform denial-of-service attacks on the application. Abusing the XXE vulnerability enabled assessors to read local files remotely. Although with the level of privileges assessors had this was limited to one-line files. With the ability to write to the database, any file could have been read. Additionally, assessors noted, with local testing, the server could be crashed by passing in improperly formatted XML. ### Patches The users should aim to use the latest released version compatible with their Neo4j version. The minimum versions containing patch ...