Package Instance

Path traversal attack
When using the Index Replication feature, Apache Solr nodes can pull index files from a master/leader node using an HTTP API which accepts a file name Solr does not validate the file name, hence it is possible to craft a special request involving path traversal, leaving any file readable to the Solr server process exposed. Solr servers protected and restricted by firewall rules and/or authentication would not be at risk since only trusted clients and users would gain direct HTTP access.

Incorrect Authorization
When using `ConfigurableInternodeAuthHadoopPlugin` for authentication, Apache Solr would forward/proxy distributed requests using server credentials instead of original client credentials. This would result in incorrect authorization resolution on the receiving hosts.

Improper Restriction of XML External Entity Reference
This vulnerability in Apache Solr relates to an XML external entity expansion (XXE) in Solr config files.

Insufficiently Protected Credentials
When starting Apache Solr, configured with the `SaslZkACLProvider` or `VMParamsAllAndReadonlyDigestZkACLProvider` and no existing `security.json` `znode`, if the optional read-only user is configured then Solr would not treat that node as a sensitive path and would allow it to be readable. Additionally, with any `ZkACLProvider`, if the `security.json` is already present, Solr will not automatically update the ACLs.

Privilege escalation
Solr's Kerberos plugin can be configured to use delegation tokens, which allows an application to reuse the authentication of an end-user or another application. There are two issues with this functionality (when using `SecurityAwareZkACLProvider` type of ACL provider e.g. `SaslZkACLProvider`). Firstly, access to the security configuration can be leaked to users other than the solr super user. Secondly, malicious users can exploit this leaked configuration for privilege escalation to further expose/modify private data and/or disrupt operations in the Solr cluster.

XEE vulnerability via DIH's dataConfig request parameter
This vulnerability relates to an XML external entity expansion (XXE) in the `&dataConfig=<inlinexml>` parameter of Solr's DataImportHandler. It can be used as XXE using file/ftp/http protocols in order to read arbitrary local files from the Solr server or the internal network.

Server-Side Request Forgery (SSRF) in org.apache.solr:solr-core
Server Side Request Forgery in Apache Solr, versions 1.3 until 7.6 (inclusive). Since the "shards" parameter does not have a corresponding whitelist mechanism, a remote attacker with access to the server could make Solr perform an HTTP GET request to any reachable URL.

Deserialization of Untrusted Data
In Apache Solr versions, the Config API allows to configure the JMX server via an HTTP POST request. By pointing it to a malicious RMI server, an attacker could take advantage of Solr's unsafe deserialization to trigger remote code execution on the Solr side.

Security Vulnerability in secure inter-node communication
This package uses a PKI based mechanism to secure inter-node communication when security is enabled. It is possible to create a specially crafted node name that does not exist as part of the cluster and point it to a malicious node. This can trick the nodes in cluster to believe that the malicious node is a member of the cluster. So, if Solr users have enabled BasicAuth authentication mechanism using the BasicAuthPlugin or if the user has implemented a custom Authentication plugin, which does not implement either `HttpClientInterceptorPlugin` or `HttpClientBuilderPlugin`, his/her servers are vulnerable to this attack. Users who only use SSL without basic authentication or those who use Kerberos are not affected.

Improper Input Validation
Reported in SOLR-14515 (private) and fixed in SOLR-14561 (public), released in Solr version 8.6.0. The Replication handler allows commands backup, restore and deleteBackup. Each of these take a location parameter, which was not validated, i.e you could read/write to any location the solr user can access.

XML External Entity (XXE) Injection in Apache Solr
In Apache Solr, the DataImportHandler, an optional but popular module to pull in data from databases and other sources, has a feature in which the whole DIH configuration can come from a request's "dataConfig" parameter. The debug mode of the DIH admin screen uses this to allow convenient debugging / development of a DIH config. Since a DIH config can contain scripts, this parameter is a security risk. Starting with version 8.2.0 of Solr, use of this parameter requires setting the Java System property "enable.dih.dataConfigParam" to true.