Vulnerabilities > CVE-2004-1653 - Remote Security vulnerability in OpenSSH

047910
CVSS 6.4 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
NONE
network
low complexity
openbsd
nessus

Summary

The default configuration for OpenSSH enables AllowTcpForwarding, which could allow remote authenticated users to perform a port bounce, when configured with an anonymous access program such as AnonCVS.

Nessus

  • NASL familyMisc.
    NASL idOPENSSH_TCP_FORWARDING.NASL
    descriptionAccording to its banner, the remote host is running OpenSSH, version 2.3.0 or later. Such versions of OpenSSH allow forwarding TCP connections. If the OpenSSH server is configured to allow anonymous connections (e.g. AnonCVS), remote, unauthenticated users could use the host as a proxy.
    last seen2020-06-01
    modified2020-06-02
    plugin id17744
    published2011-12-01
    reporterThis script is Copyright (C) 2011-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/17744
    titleOpenSSH >= 2.3.0 AllowTcpForwarding Port Bouncing
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(17744);
      script_version("1.4");
      script_cvs_date("Date: 2018/11/15 20:50:23");
    
      script_cve_id("CVE-2004-1653");
    
      script_name(english:"OpenSSH >= 2.3.0 AllowTcpForwarding Port Bouncing");
      script_summary(english:"Checks for remote SSH version.");
    
      script_set_attribute(attribute:"synopsis", value:
    "The remote SSH server may permit anonymous port bouncing.");
      script_set_attribute(attribute:"description", value:
    "According to its banner, the remote host is running OpenSSH, version
    2.3.0 or later.  Such versions of OpenSSH allow forwarding TCP
    connections.  If the OpenSSH server is configured to allow anonymous
    connections (e.g. AnonCVS), remote, unauthenticated users could use
    the host as a proxy.");
    
      script_set_attribute(attribute:"see_also", value:"https://marc.info/?l=bugtraq&m=109413637313484&w=2");
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2c86d008");
    
      script_set_attribute(attribute:"solution", value:
    "Disallow anonymous users, set AllowTcpForwarding to 'no', or use the
    Match directive to restrict anonymous users.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2004/08/21");
      script_set_attribute(attribute:"plugin_publication_date", value:"2011/12/01");
    
      script_set_attribute(attribute:"plugin_type", value:"remote");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:openbsd:openssh");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2011-2018 Tenable Network Security, Inc.");
      script_family(english:"Misc.");
    
      script_dependencies("ssh_detect.nasl");
      script_require_ports("Services/ssh", 22);
    
      exit(0);
    }
    
    include("global_settings.inc");
    include("misc_func.inc");
    
    # Only PCI considers this an issue.
    if (!get_kb_item("Settings/PCI_DSS")) exit(0, "PCI-DSS compliance checking is not enabled.");
    
    # Ensure the port is open.
    port = get_service(svc:"ssh", exit_on_fail:TRUE);
    
    # Get banner for service.
    banner = tolower(get_kb_item_or_exit("SSH/banner/" + port));
    if ("openssh" >!< banner) exit(0, "The SSH service on port " + port + " is not OpenSSH.");
    
    # Check the version in the banner.
    match = eregmatch(string:banner, pattern:"openssh[-_]([0-9][-._0-9a-z]+)");
    if (isnull(match)) exit(1, "Could not parse the version string in the banner from port "+port+".");
    version = match[1];
    
    # Extract the numeric portion of the version number.
    match = eregmatch(string:version, pattern:"([0-9.]+)");
    if (isnull(match)) exit(1, 'Failed to parse the version (' + version + ') of the OpenSSH server listening on port '+port+'.');
    ver = match[1];
    
    if (ver_compare(ver:ver, fix:"2.3.0", strict:FALSE) < 0)
      exit(0, "The OpenSSH server on port " + port + " is not affected as it's version " + version + ".");
    
    if (report_verbosity > 0)
    {
      report =
        '\n  Version source    : ' + banner +
        '\n  Installed version : ' + version +
        '\n';
      security_warning(port:port, extra:report);
    }
    else security_warning(port);
    
  • NASL familyMisc.
    NASL idSUNSSH_PLAINTEXT_RECOVERY.NASL
    descriptionThe version of SunSSH running on the remote host has an information disclosure vulnerability. A design flaw in the SSH specification could allow a man-in-the-middle attacker to recover up to 32 bits of plaintext from an SSH-protected connection in the standard configuration. An attacker could exploit this to gain access to sensitive information. Note that this version of SunSSH is also prone to several additional issues but Nessus did not test for them.
    last seen2020-06-01
    modified2020-06-02
    plugin id55992
    published2011-08-29
    reporterThis script is Copyright (C) 2011-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/55992
    titleSunSSH < 1.1.1 / 1.3 CBC Plaintext Disclosure
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    
    
    include("compat.inc");
    
    
    if (description)
    {
      script_id(55992);
      script_version("1.17");
      script_cvs_date("Date: 2018/07/31 17:27:54");
    
      script_cve_id(
        "CVE-2000-0525",
        "CVE-2000-1169",
        "CVE-2001-0361",
        "CVE-2001-0529",
        "CVE-2001-0572",
        "CVE-2001-0816",
        "CVE-2001-0872",
        "CVE-2001-1380",
        "CVE-2001-1382",
        "CVE-2001-1459",
        "CVE-2001-1507",
        "CVE-2001-1585",
        "CVE-2002-0083",
        "CVE-2002-0575",
        "CVE-2002-0639",
        "CVE-2002-0640",
        "CVE-2002-0765",
        "CVE-2003-0190",
        "CVE-2003-0386",
        "CVE-2003-0682",
        "CVE-2003-0693",
        "CVE-2003-0695",
        "CVE-2003-0786",
        "CVE-2003-0787",
        "CVE-2003-1562",
        "CVE-2004-0175",
        "CVE-2004-1653",
        "CVE-2004-2069",
        "CVE-2004-2760",
        "CVE-2005-2666",
        "CVE-2005-2797",
        "CVE-2005-2798",
        "CVE-2006-0225",
        "CVE-2006-4924",
        "CVE-2006-4925",
        "CVE-2006-5051",
        "CVE-2006-5052",
        "CVE-2006-5229",
        "CVE-2006-5794",
        "CVE-2007-2243",
        "CVE-2007-2768",
        "CVE-2007-3102",
        "CVE-2007-4752",
        "CVE-2008-1483",
        "CVE-2008-1657",
        "CVE-2008-3259",
        "CVE-2008-4109",
        "CVE-2008-5161"
      );
      script_bugtraq_id(32319);
      script_xref(name:"CERT", value:"958563");
    
      script_name(english:"SunSSH < 1.1.1 / 1.3 CBC Plaintext Disclosure");
      script_summary(english:"Checks SSH banner");
    
      script_set_attribute(
        attribute:"synopsis",
        value:
    "The SSH service running on the remote host has an information
    disclosure vulnerability."
      );
      script_set_attribute(
        attribute:"description",
        value:
    "The version of SunSSH running on the remote host has an information
    disclosure vulnerability.  A design flaw in the SSH specification
    could allow a man-in-the-middle attacker to recover up to 32 bits of
    plaintext from an SSH-protected connection in the standard
    configuration.  An attacker could exploit this to gain access to
    sensitive information.
    
    Note that this version of SunSSH is also prone to several additional
    issues but Nessus did not test for them." );
    
      # http://web.archive.org/web/20090523091544/http://www.cpni.gov.uk/docs/vulnerability_advisory_ssh.txt
      script_set_attribute(attribute:"see_also",value:"http://www.nessus.org/u?4984aeb9");
      # http://hub.opensolaris.org/bin/view/Community+Group+security/SSH#HHistoryofSunSSH
      script_set_attribute(attribute:"see_also",value:"http://www.nessus.org/u?b679208a");
      script_set_attribute(attribute:"see_also",value:"http://blogs.oracle.com/janp/entry/on_sunssh_versioning");
      script_set_attribute(
        attribute:"solution",
        value:"Upgrade to SunSSH 1.1.1 / 1.3 or later"
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
      script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
      script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
      script_set_attribute(attribute:"exploit_available", value:"true");
      script_set_attribute(attribute:"exploit_framework_core", value:"true");
      script_cwe_id(16, 20, 22, 189, 200, 255, 264, 287, 310, 362, 399);
      script_set_attribute(attribute:"vuln_publication_date",value:"2008/11/17");
      script_set_attribute(attribute:"patch_publication_date",value:"2008/12/11");
      script_set_attribute(attribute:"plugin_publication_date",value:"2011/08/29");
      script_set_attribute(attribute:"plugin_type",value:"remote");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_family(english:"Misc.");
    
      script_copyright(english:"This script is Copyright (C) 2011-2018 Tenable Network Security, Inc.");
    
      script_dependencies("ssh_detect.nasl");
      script_require_ports("Services/ssh");
    
      exit(0);
    }
    
    include("global_settings.inc");
    include("misc_func.inc");
    
    # Ensure the port is open.
    port = get_service(svc:"ssh", default:22, exit_on_fail:TRUE);
    
    # Get banner for service.
    banner = get_kb_item_or_exit("SSH/banner/" + port);
    
    # Check that we're using SunSSH.
    if ('sun_ssh' >!< tolower(banner))
      exit(0, "The SSH service on port " + port + " is not SunSSH.");
    
    # Check the version in the banner.
    match = eregmatch(string:banner, pattern:"sun_ssh[-_]([0-9.]+)$", icase:TRUE);
    if (isnull(match))
      exit(1, "Could not parse the version string from the banner on port " + port + ".");
    else
      version = match[1];
    
    # the Oracle (Sun) blog above explains how the versioning works. we could
    # probably explicitly check for each vulnerable version if it came down to it
    if (
      ver_compare(ver:version, fix:'1.1.1', strict:FALSE) == -1 ||
      version == '1.2'
    )
    {
      if (report_verbosity > 0)
      {
        report =
          '\n  Version source    : ' + banner +
          '\n  Installed version : ' + version +
          '\n  Fixed version     : 1.1.1 / 1.3\n';
        security_hole(port:port, extra:report);
      }
      else security_hole(port);
    }
    else exit(0, "The SunSSH server on port "+port+" is not affected as it's version "+version+".");
    

Statements

contributorTomas Hoger
lastmodified2009-11-25
organizationRed Hat
statementPermitting TCP forwarding is the expected and known default configuration. If it is not desired, it can disabled using the AllowTcpForwarding option in the /etc/ssh/sshd_config configuration file. However, only disabling TCP forwarding does not improve security unless users are also denied shell access. For more information, see man sshd_config.

The Hacker News

idTHN:40526DA432A70837B02920D544EFE6D8
last seen2018-01-27
modified2016-10-14
published2016-10-13
reporterMohit Kumar
sourcehttps://thehackernews.com/2016/10/sshowdown-iot-security.html
title12-Year-Old SSH Bug Exposes More than 2 Million IoT Devices