ProFTPD < 1.3.5e / 1.3.6x < 1.3.6rc5 AllowChrootSymlinks bypass

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

include('compat.inc');

if (description)
{
  script_id(106756);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/10/29");

  script_cve_id("CVE-2017-7418");
  script_bugtraq_id(97409);

  script_name(english:"ProFTPD < 1.3.5e / 1.3.6x < 1.3.6rc5 AllowChrootSymlinks bypass");

  script_set_attribute(attribute:"synopsis", value:
"The remote FTP server is affected by a mitigation bypass vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote host is using ProFTPD, a free FTP server for Unix and
Linux.
According to its banner, the version of ProFTPD installed on the
remote host is prior to 1.3.5e or 1.3.6x prior to 1.3.6rc5
and is affected by an issue where an attacker who is not granted 
full filesystem access may reconfigure the home directory of an 
FTP user.");
  script_set_attribute(attribute:"see_also", value:"http://bugs.proftpd.org/show_bug.cgi?id=4295");
  script_set_attribute(attribute:"solution", value:
"Upgrade to ProFTPD version 1.3.5e / 1.3.6rc5 or later.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-7418");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/03/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/04/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/02/12");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:proftpd:proftpd");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"FTP");

  script_copyright(english:"This script is Copyright (C) 2018-2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ftp_overflow.nasl", "ftpserver_detect_type_nd_version.nasl");
  script_require_keys("ftp/proftpd", "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);

port = get_ftp_port(default: 21, broken:TRUE);

app = "ProFTPD";
banner = get_ftp_banner(port:port);
if (!banner) audit(AUDIT_NO_BANNER, port);
if (app >!< banner) audit(AUDIT_NOT_DETECT, app, port);

matches = pregmatch(string:banner, pattern:"ProFTPD ([0-9a-z.]+) ");
if (isnull(matches)) audit(AUDIT_SERVICE_VER_FAIL, app, port);
version = matches[1];

if (version =~ '^1(\\.3)?$') audit(AUDIT_VER_NOT_GRANULAR, app, version);

if (
  version =~ "^0($|\.)" ||
  version =~ "^1\.[0-2]($|\.)" ||
  version =~ "^1\.3\.[1234]($|[^0-9])" ||
  version =~ "^1\.3\.5(rc[1-9]|[abcd])?($|[^0-9e-z])" ||
  version =~ "^1\.3\.6(rc[1234])?($|[^0-9a-z])"
)
{
  report =
    '\n  Version source    : ' + chomp(banner) +
    '\n  Installed version : ' + version +
    '\n  Fixed version     : 1.3.5e / 1.3.6rc5\n';
  security_report_v4(severity:SECURITY_NOTE, port:port, extra:report);
  exit(0);
}
else audit(AUDIT_LISTEN_NOT_VULN, app, port, version);