Multiple FTP Server quote stat Command Traversal Arbitrary Directory Access

#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
 script_id(11679);
 script_version("1.24");
 script_cvs_date("Date: 2018/08/08 12:52:14");

 script_bugtraq_id(7718);

 script_name(english:"Multiple FTP Server quote stat Command Traversal Arbitrary Directory Access");
 script_summary(english:"Attempts to break out of the FTP root");

 script_set_attribute(attribute:"synopsis", value:"The remote FTP server is prone to a directory traversal attack.");
 script_set_attribute(attribute:"description", value:
"The remote FTP server is vulnerable to a flaw that allows users to
access files outside the FTP server root.

An attacker may break out of his FTP jail by issuing the command :

ftp> quote stat ../*

Some versions of VisNetic FTP Server and Titan FTP Server are known to
be affected by this issue.");
 script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?f82b50d3");
 script_set_attribute(attribute:"solution", value:"Contact your vendor for a patch.");
 script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N");
 script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
 script_set_attribute(attribute:"exploitability_ease", value:"No exploit is required");
 script_set_attribute(attribute:"exploit_available", value:"true");

 script_set_attribute(attribute:"vuln_publication_date", value:"2003/05/29");
 script_set_attribute(attribute:"plugin_publication_date", value:"2003/06/02");

 script_set_attribute(attribute:"potential_vulnerability", value:"true");
 script_set_attribute(attribute:"plugin_type", value:"remote");
 script_end_attributes();

 script_category(ACT_GATHER_INFO);

 script_copyright(english:"This script is Copyright (C) 2003-2018 Tenable Network Security, Inc.");
 script_family(english:"FTP");

 script_dependencie("ftpserver_detect_type_nd_version.nasl", "ftp_anonymous.nasl");
 script_require_keys("ftp/login", "Settings/ParanoidReport");
 script_require_ports("Services/ftp", 21);

 exit(0);
}


include("audit.inc");
include("ftp_func.inc");
include("global_settings.inc");

if (report_paranoia < 2) audit(AUDIT_PARANOID);

global_var port, soc;

function dir()
{
 local_var ls, p, r, result, soc2;

 p = ftp_pasv(socket:soc);
 if (!p) exit(1, "Cannot get FTP passive port from control port "+port+".");
 soc2 = open_sock_tcp(p, transport:get_port_transport(port));
 if(!soc2)return(0);
 ls = string("LIST .\r\n");
 send(socket:soc, data:ls);
 r = ftp_recv_line(socket:soc);
 if(egrep(pattern:"^150 ", string:r))
 {
  result = ftp_recv_listing(socket:soc2);
  close(soc2);
  r = ftp_recv_line(socket:soc);
  return(result);
 }
 return(0);
}


#
# The script code starts here
#

port = get_ftp_port(default: 21);

soc = open_sock_tcp(port);
if(! soc) exit(1, "TCP connection failed to port "+port+".");

 login = get_kb_item("ftp/login");
 pass = get_kb_item("ftp/password");
 if(ftp_authenticate(socket:soc, user:login, pass:pass))
 {
 send(socket:soc, data: 'stat /\r\n');
 r = ftp_recv_line(socket:soc);
 listing0 = dir();
 if(!listing0) exit(1, "Cannot read FTP answer from port "+port+".");

 send(socket:soc, data: 'stat ../*\r\n');
 r = ftp_recv_line(socket:soc);
 listing1 = dir();
 if(!listing1) exit(1, "Cannot read FTP answer from port "+port+".");

 send(socket:soc, data: 'CWD C:\r\n');
 r = ftp_recv_line(socket:soc);
 listing2 = dir();
 if(!listing2) exit(1, "Cannot read FTP answer from port "+port+".");

 send(socket:soc, data: 'CWD /\r\n');
 r = ftp_recv_line(socket:soc);
 listing3 = dir();
 if(!listing3) exit(1, "Cannot read FTP answer from port "+port+".");

 close(soc);

 if(listing0 != listing1 ||
    listing2 != listing3 ) security_warning(port:port, extra:'\nstat / returns :\n' + listing0 + '\n\nstat ../* returns :\n', listing1, '\n\nCWD / and NLST return :\n' + listing3 + '\n\nCWD C: and NLST return :\n' + listing2);
 }