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nmap_ftp.cc
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357 lines (329 loc) · 13.2 KB
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/***************************************************************************
* nmap_ftp.cc -- Nmap's FTP routines used for FTP bounce scan (-b)
* *
***********************IMPORTANT NMAP LICENSE TERMS************************
*
* The Nmap Security Scanner is (C) 1996-2026 Nmap Software LLC ("The Nmap
* Project"). Nmap is also a registered trademark of the Nmap Project.
*
* This program is distributed under the terms of the Nmap Public Source
* License (NPSL). The exact license text applying to a particular Nmap
* release or source code control revision is contained in the LICENSE
* file distributed with that version of Nmap or source code control
* revision. More Nmap copyright/legal information is available from
* https://nmap.org/book/man-legal.html, and further information on the
* NPSL license itself can be found at https://nmap.org/npsl/ . This
* header summarizes some key points from the Nmap license, but is no
* substitute for the actual license text.
*
* Nmap is generally free for end users to download and use themselves,
* including commercial use. It is available from https://nmap.org.
*
* The Nmap license generally prohibits companies from using and
* redistributing Nmap in commercial products, but we sell a special Nmap
* OEM Edition with a more permissive license and special features for
* this purpose. See https://nmap.org/oem/
*
* If you have received a written Nmap license agreement or contract
* stating terms other than these (such as an Nmap OEM license), you may
* choose to use and redistribute Nmap under those terms instead.
*
* The official Nmap Windows builds include the Npcap software
* (https://npcap.com) for packet capture and transmission. It is under
* separate license terms which forbid redistribution without special
* permission. So the official Nmap Windows builds may not be redistributed
* without special permission (such as an Nmap OEM license).
*
* Source is provided to this software because we believe users have a
* right to know exactly what a program is going to do before they run it.
* This also allows you to audit the software for security holes.
*
* Source code also allows you to port Nmap to new platforms, fix bugs, and
* add new features. You are highly encouraged to submit your changes as a
* Github PR or by email to the dev@nmap.org mailing list for possible
* incorporation into the main distribution. Unless you specify otherwise, it
* is understood that you are offering us very broad rights to use your
* submissions as described in the Nmap Public Source License Contributor
* Agreement. This is important because we fund the project by selling licenses
* with various terms, and also because the inability to relicense code has
* caused devastating problems for other Free Software projects (such as KDE
* and NASM).
*
* The free version of Nmap is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Warranties,
* indemnification and commercial support are all available through the
* Npcap OEM program--see https://nmap.org/oem/
*
***************************************************************************/
/* $Id$ */
#include "nmap.h"
#include "nmap_ftp.h"
#include "output.h"
#include "NmapOps.h"
#include "nmap_error.h"
#include "tcpip.h"
#include "Target.h"
#include "nmap_tty.h"
extern NmapOps o;
struct ftpinfo get_default_ftpinfo(void) {
#if (defined(IN_ADDR_DEEPSTRUCT) || defined(SOLARIS))
/* Note that struct in_addr in solaris is 3 levels deep just to store an
* unsigned int! */
struct ftpinfo ftp = { FTPUSER, FTPPASS, "", { { { 0 } } } , 21, 0};
#else
struct ftpinfo ftp = { FTPUSER, FTPPASS, "", { 0 }, 21, 0};
#endif
return ftp;
}
/* parse a URL stype ftp string of the form user:pass@server:portno */
int parse_bounce_argument(struct ftpinfo *ftp, char *url) {
char *p = url, *q, *s;
if ((q = strrchr(url, '@'))) { /* we have user and/or pass */
*q++ = '\0';
if ((s = strchr(p, ':'))) { /* we have user AND pass */
*s++ = '\0';
strncpy(ftp->pass, s, 255);
} else { /* we ONLY have user */
log_write(LOG_STDOUT, "Assuming %s is a username, and using the default password: %s\n",
p, ftp->pass);
}
strncpy(ftp->user, p, 63);
} else {
q = url;
}
/* q points to beginning of server name */
if ((s = strchr(q, ':'))) { /* we have portno */
*s++ = '\0';
ftp->port = atoi(s);
}
strncpy(ftp->server_name, q, FQDN_LEN+1);
ftp->user[63] = ftp->pass[255] = ftp->server_name[FQDN_LEN] = 0;
return 1;
}
int ftp_anon_connect(struct ftpinfo *ftp) {
int sd;
struct sockaddr_in sock;
int res;
char recvbuf[2048];
char command[512];
if (o.verbose || o.debugging)
log_write(LOG_STDOUT, "Attempting connection to ftp://%s:%s@%s:%i\n",
ftp->user, ftp->pass, ftp->server_name, ftp->port);
if ((sd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
gh_perror("Couldn't create %s socket", __func__);
return 0;
}
socket_bindtodevice(sd, o.device);
sock.sin_family = AF_INET;
sock.sin_addr.s_addr = ftp->server.s_addr;
sock.sin_port = htons(ftp->port);
res = connect(sd, (struct sockaddr *) &sock, sizeof(struct sockaddr_in));
if (res < 0)
fatal("Your FTP bounce proxy server won't talk to us!");
if (o.verbose || o.debugging)
log_write(LOG_STDOUT, "Connected:");
while ((res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 7, NULL)) > 0) {
if (o.debugging || o.verbose) {
recvbuf[res] = '\0';
log_write(LOG_STDOUT, "%s", recvbuf);
}
}
if (res < 0)
pfatal("recv problem from FTP bounce server");
Snprintf(command, 511, "USER %s\r\n", ftp->user);
send(sd, command, strlen(command), 0);
res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 12, NULL);
if (res <= 0)
pfatal("recv problem from FTP bounce server");
recvbuf[res] = '\0';
if (o.debugging)
log_write(LOG_STDOUT, "sent username, received: %s", recvbuf);
if (recvbuf[0] == '5')
fatal("Your FTP bounce server doesn't like the username \"%s\"", ftp->user);
if (!strncmp(recvbuf, "230", 3)) {
// 230 User logged in
// No need to send PASS
if (o.verbose)
log_write(LOG_STDOUT, "Login credentials accepted by FTP server!\n");
ftp->sd = sd;
return sd;
}
Snprintf(command, 511, "PASS %s\r\n", ftp->pass);
send(sd, command, strlen(command), 0);
res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 12, NULL);
if (res < 0)
pfatal("recv problem from FTP bounce server");
if (!res) {
error("Timeout from bounce server ...");
} else {
recvbuf[res] = '\0';
if (o.debugging)
log_write(LOG_STDOUT, "sent password, received: %s", recvbuf);
if (recvbuf[0] == '5')
fatal("Your FTP bounce server refused login combo (%s/%s)", ftp->user, ftp->pass);
}
while ((res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 2, NULL)) > 0) {
if (o.debugging) {
recvbuf[res] = '\0';
log_write(LOG_STDOUT, "%s", recvbuf);
}
}
if (res < 0)
pfatal("recv problem from FTP bounce server");
if (o.verbose)
log_write(LOG_STDOUT, "Login credentials accepted by FTP server!\n");
ftp->sd = sd;
return sd;
}
/* FTP bounce attack scan. This function is rather lame and should be
rewritten. But I don't think it is used much anyway. If I'm going to
allow FTP bounce scan, I should really allow SOCKS proxy scan. */
void bounce_scan(Target *target, u16 *portarray, int numports,
struct ftpinfo *ftp) {
o.current_scantype = BOUNCE_SCAN;
ScanProgressMeter *SPM;
int res , sd = ftp->sd, i = 0;
const char *t = (const char *)target->v4hostip();
int retriesleft = FTP_RETRIES;
char recvbuf[2048];
char targetstr[20];
char command[512];
unsigned short portno, p1, p2;
int timedout;
bool privok = false;
if (numports == 0)
return; /* nothing to scan for */
Snprintf(targetstr, 20, "%d,%d,%d,%d,", UC(t[0]), UC(t[1]), UC(t[2]), UC(t[3]));
SPM = new ScanProgressMeter(scantype2str(BOUNCE_SCAN));
for (i = 0; i < numports; i++) {
/* Check for timeout */
if (target->timedOut(NULL)) {
Snprintf(recvbuf, sizeof(recvbuf), "Target timed out");
SPM->endTask(NULL, recvbuf);
delete SPM;
return;
}
portno = htons(portarray[i]);
p1 = ((unsigned char *) &portno)[0];
p2 = ((unsigned char *) &portno)[1];
Snprintf(command, 512, "PORT %s%i,%i\r\n", targetstr, p1, p2);
if (o.debugging)
log_write(LOG_STDOUT, "Attempting command: %s", command);
if (send(sd, command, strlen(command), 0) < 0 ) {
gh_perror("send in %s", __func__);
if (retriesleft) {
if (o.verbose || o.debugging)
log_write(LOG_STDOUT, "Our FTP proxy server hung up on us! retrying\n");
retriesleft--;
close(sd);
ftp->sd = ftp_anon_connect(ftp);
if (ftp->sd < 0) {
Snprintf(recvbuf, sizeof(recvbuf), "Error connecting");
SPM->endTask(NULL, recvbuf);
delete SPM;
return;
}
sd = ftp->sd;
i--;
} else {
error("Our socket descriptor is dead and we are out of retries. Giving up.");
close(sd);
ftp->sd = -1;
Snprintf(recvbuf, sizeof(recvbuf), "Max retries exceeded");
SPM->endTask(NULL, recvbuf);
delete SPM;
return;
}
} else { /* Our send is good */
res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 15, NULL);
if (res <= 0) {
perror("recv problem from FTP bounce server");
} else { /* our recv is good */
recvbuf[res] = '\0';
if (o.debugging)
log_write(LOG_STDOUT, "result of port query on port %i: %s",
portarray[i], recvbuf);
if (recvbuf[0] == '5' && !privok) {
if (portarray[i] > 1023) {
fatal("Your FTP bounce server sucks, it won't let us feed bogus ports!");
} else {
error("Your FTP bounce server doesn't allow privileged ports, skipping them.");
while (i < numports && portarray[i] < 1024) i++;
if (i >= numports) {
fatal("And you didn't want to scan any unprivileged ports. Giving up.");
}
}
} else { /* Not an error message */
if (portarray[i] < 1024) {
privok = true;
}
if (send(sd, "LIST\r\n", 6, 0) > 0 ) {
res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 12, &timedout);
if (res < 0) {
perror("recv problem from FTP bounce server");
} else if (res == 0) {
recvbuf[res] = '\0';
if (timedout)
target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_FILTERED);
else target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_CLOSED);
} else {
recvbuf[res] = '\0';
if (o.debugging)
log_write(LOG_STDOUT, "result of LIST: %s", recvbuf);
if (!strncmp(recvbuf, "500", 3)) {
/* oh dear, we are not aligned properly */
if (o.verbose || o.debugging)
error("FTP command misalignment detected ... correcting.");
res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 10, NULL);
}
if (recvbuf[0] == '1') {
res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 10, &timedout);
if (res < 0)
perror("recv problem from FTP bounce server");
else if (timedout || res == 0) {
// Timed out waiting for LIST to complete; probably filtered.
if(send(sd, "ABOR\r\n", 6, 0) > 0) {
target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_FILTERED);
}
// Get response and discard
res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 10, &timedout);
recvbuf[0] = '\0';
goto nextport;
}
else {
recvbuf[res] = '\0';
if (o.debugging)
log_write(LOG_STDOUT, "nxt line: %s", recvbuf);
if (recvbuf[0] == '4' && recvbuf[1] == '2' && recvbuf[2] == '6') {
target->ports.forgetPort(portarray[i], IPPROTO_TCP);
if (o.debugging || o.verbose)
log_write(LOG_STDOUT, "Changed my mind about port %i\n", portarray[i]);
}
}
}
if (recvbuf[0] == '2') {
target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_OPEN);
} else {
/* This means the port is closed ... */
target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_CLOSED);
}
}
}
}
}
}
nextport:
if (SPM->mayBePrinted(NULL)) {
SPM->printStatsIfNecessary((double) i / numports, NULL);
}
else if (keyWasPressed()) {
SPM->printStats((double) i / numports, NULL);
log_flush(LOG_STDOUT);
}
}
Snprintf(recvbuf, sizeof(recvbuf), "%d total ports", numports);
SPM->endTask(NULL, recvbuf);
delete SPM;
return;
}
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