Description
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 and 4.4.0.14 (4.4 branch) 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.
Remediation
References
https://github.com/neo4j/apoc/pull/310
https://github.com/neo4j/apoc/releases/tag/5.5.0
https://github.com/neo4j/apoc/security/advisories/GHSA-6wxg-wh7f-rqpr
https://neo4j.com/docs/operations-manual/current/reference/configuration-settings/#config_dbms.security.procedures.allowlist
Related Vulnerabilities
CVE-2018-25031 Vulnerability in maven package org.webjars.npm:swagger-ui-dist
CVE-2018-20676 Vulnerability in maven package org.webjars.bower:bootstrap-sass
CVE-2018-14731 Vulnerability in npm package parcel-bundler
CVE-2021-28860 Vulnerability in npm package mixme
CVE-2018-16131 Vulnerability in maven package com.typesafe.akka:akka-http-core_2.11