SSL/TLS: RSA Temporary Key Handling 'RSA_EXPORT' Downgrade Issue (FREAK)

# SPDX-FileCopyrightText: 2015 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("1.3.6.1.4.1.25623.1.0.805142");
  script_version("2026-06-03T07:18:10+0000");
  script_cve_id("CVE-2015-0204");
  script_tag(name:"cvss_base", value:"4.3");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:M/Au:N/C:N/I:P/A:N");
  script_tag(name:"last_modification", value:"2026-06-03 07:18:10 +0000 (Wed, 03 Jun 2026)");
  script_tag(name:"creation_date", value:"2015-03-06 16:42:13 +0530 (Fri, 06 Mar 2015)");
  script_name("SSL/TLS: RSA Temporary Key Handling 'RSA_EXPORT' Downgrade Issue (FREAK)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2015 Greenbone AG");
  script_family("SSL and TLS");
  script_dependencies("gb_ssl_tls_ciphers_gathering.nasl");
  script_mandatory_keys("ssl_tls/ciphers/supported_ciphers", "ssl_tls/port");

  script_xref(name:"URL", value:"https://freakattack.com");
  script_xref(name:"URL", value:"https://openssl-library.org/news/secadv/20150108.txt");
  script_xref(name:"URL", value:"https://web.archive.org/web/20210122095002/http://www.securityfocus.com/bid/71936");
  script_xref(name:"URL", value:"https://www.secpod.com/blog/freak-attack");
  script_xref(name:"URL", value:"https://blog.cryptographyengineering.com/2015/03/03/attack-of-week-freak-or-factoring-nsa");
  script_xref(name:"URL", value:"https://configurator.tlsref.org/");
  # nb: Some of the BSI documents are only available in German and thus no english variants have
  # been used here.
  script_xref(name:"URL", value:"https://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/Publications/TechGuidelines/TG02102/BSI-TR-02102-1.html");
  script_xref(name:"URL", value:"https://www.bsi.bund.de/EN/Themen/Oeffentliche-Verwaltung/Mindeststandards/TLS-Protokoll/TLS-Protokoll_node.html");
  script_xref(name:"URL", value:"https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Publikationen/TechnischeRichtlinien/TR03116/BSI-TR-03116-4.html");
  script_xref(name:"URL", value:"https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Mindeststandards/Mindeststandard_BSI_TLS_Version_2_4.html");
  script_xref(name:"URL", value:"https://web.archive.org/web/20240113175943/https://www.bettercrypto.org");
  script_xref(name:"URL", value:"https://www.enisa.europa.eu/publications/algorithms-key-size-and-parameters-report-2014");

  script_tag(name:"summary", value:"This host is accepting 'RSA_EXPORT' cipher suites and is prone
  to a man-in-the-middle (MITM) vulnerability.");

  script_tag(name:"vuldetect", value:"Checks previous collected cipher suites.");

  script_tag(name:"insight", value:"Flaw is due to improper handling RSA temporary keys in a
  non-export RSA key exchange cipher suite.");

  script_tag(name:"impact", value:"Successful exploitation will allow remote attacker to downgrade
  the security of a session to use 'RSA_EXPORT' cipher suites, which are significantly weaker than
  non-export cipher suites. This may allow a man-in-the-middle attacker to more easily break the
  encryption and monitor or tamper with the encrypted stream.");

  script_tag(name:"affected", value:"- Hosts accepting 'RSA_EXPORT' cipher suites.

  - OpenSSL versions prior to 0.9.8zd, 1.0.0 prior to 1.0.0p and 1.0.1 prior to 1.0.1k.");

  script_tag(name:"solution", value:"- Remove support for 'RSA_EXPORT' cipher suites from the
  service. Please see the references for more resources supporting you with this task.

  - If the service is using OpenSSL: Update to version 0.9.8zd, 1.0.0p, 1.0.1k or later.");

  script_tag(name:"qod_type", value:"remote_banner");
  script_tag(name:"solution_type", value:"VendorFix");

  exit(0);
}

include("ssl_funcs.inc");
include("host_details.inc");

cipherText = "'RSA_EXPORT' cipher suites";

if( ! port = tls_ssl_get_port() )
  exit( 0 );

if( ! sup_ssl = tls_get_supported_kb_versions( port:port ) )
  exit( 0 );

if( "SSLv3" >< sup_ssl ) {
  sslv3CipherList = tls_get_supported_kb_ciphers( port:port, version:"sslv3" );

  if( ! isnull( sslv3CipherList ) ) {

    # Sort to not report changes on delta reports if just the order is different
    sslv3CipherList = sort( sslv3CipherList );

    foreach sslv3Cipher( sslv3CipherList ) {
      if( "_RSA_EXPORT_" >< sslv3Cipher ) {
        sslv3Vuln = TRUE;
        sslv3tmpReport += sslv3Cipher + '\n';
      }
    }

    if( sslv3Vuln ) {
      report += cipherText + ' accepted by this service via the SSLv3 protocol:\n\n' + sslv3tmpReport + '\n';
    }
  }
}

if( "TLSv1.0" >< sup_ssl ) {
  tlsv1_0CipherList = tls_get_supported_kb_ciphers( port:port, version:"tlsv1" );

  if( ! isnull( tlsv1_0CipherList ) ) {

    # Sort to not report changes on delta reports if just the order is different
    tlsv1_0CipherList = sort( tlsv1_0CipherList );

    foreach tlsv1_0Cipher( tlsv1_0CipherList ) {
      if( "_RSA_EXPORT_" >< tlsv1_0Cipher ) {
        tlsv1_0Vuln = TRUE;
        tlsv1_0tmpReport += tlsv1_0Cipher + '\n';
      }
    }

    if( tlsv1_0Vuln ) {
      report += cipherText + ' accepted by this service via the TLSv1.0 protocol:\n\n' + tlsv1_0tmpReport + '\n';
    }
  }
}

if( "TLSv1.1" >< sup_ssl ) {
  tlsv1_1CipherList = tls_get_supported_kb_ciphers( port:port, version:"tlsv1_1" );

  if( ! isnull( tlsv1_1CipherList ) ) {

    # Sort to not report changes on delta reports if just the order is different
    tlsv1_1CipherList = sort( tlsv1_1CipherList );

    foreach tlsv1_1Cipher( tlsv1_1CipherList ) {
      if( "_RSA_EXPORT_" >< tlsv1_1Cipher ) {
        tlsv1_1Vuln = TRUE;
        tlsv1_1tmpReport += tlsv1_1Cipher + '\n';
      }
    }

    if( tlsv1_1Vuln ) {
      report += cipherText + ' accepted by this service via the TLSv1.1 protocol:\n\n' + tlsv1_1tmpReport + '\n';
    }
  }
}

if( "TLSv1.2" >< sup_ssl ) {
  tlsv1_2CipherList = tls_get_supported_kb_ciphers( port:port, version:"tlsv1_2" );

  if( ! isnull( tlsv1_2CipherList ) ) {

    # Sort to not report changes on delta reports if just the order is different
    tlsv1_2CipherList = sort( tlsv1_2CipherList );

    foreach tlsv1_2Cipher( tlsv1_2CipherList ) {
      if( "_RSA_EXPORT_" >< tlsv1_2Cipher ) {
        tlsv1_2Vuln = TRUE;
        tlsv1_2tmpReport += tlsv1_2Cipher + '\n';
      }
    }

    if( tlsv1_2Vuln ) {
      report += cipherText + ' accepted by this service via the TLSv1.2 protocol:\n\n' + tlsv1_2tmpReport + '\n';
    }
  }
}

if( report ) {

  # nb:
  # - Store the reference from this one to gb_ssl_tls_ciphers_report.nasl to show a cross-reference within the
  #   reports
  # - We don't want to use get_app_* functions as we're only interested in the cross-reference here
  register_host_detail( name:"detected_by", value:"1.3.6.1.4.1.25623.1.0.802067" ); # gb_ssl_tls_ciphers_report.nasl
  register_host_detail( name:"detected_at", value:port + "/tcp" );

  security_message( port:port, data:report );
  exit( 0 );
}

exit( 99 );