Vulnerabilities > CVE-2001-1585 - Improper Authentication vulnerability in Openbsd Openssh 2.3.1

047910
CVSS 0.0 - NONE
Attack vector
UNKNOWN
Attack complexity
UNKNOWN
Privileges required
UNKNOWN
Confidentiality impact
UNKNOWN
Integrity impact
UNKNOWN
Availability impact
UNKNOWN
openbsd
CWE-287
nessus
NVD
Published: 2001-12-31
Updated: 2024-11-20

Summary

SSH protocol 2 (aka SSH-2) public key authentication in the development snapshot of OpenSSH 2.3.1, available from 2001-01-18 through 2001-02-08, does not perform a challenge-response step to ensure that the client has the proper private key, which allows remote attackers to bypass authentication as other users by supplying a public key from that user's authorized_keys file.

Vulnerable Configurations

Part Description Count
Application
Openbsd
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Authentication Abuse
    An attacker obtains unauthorized access to an application, service or device either through knowledge of the inherent weaknesses of an authentication mechanism, or by exploiting a flaw in the authentication scheme's implementation. In such an attack an authentication mechanism is functioning but a carefully controlled sequence of events causes the mechanism to grant access to the attacker. This attack may exploit assumptions made by the target's authentication procedures, such as assumptions regarding trust relationships or assumptions regarding the generation of secret values. This attack differs from Authentication Bypass attacks in that Authentication Abuse allows the attacker to be certified as a valid user through illegitimate means, while Authentication Bypass allows the user to access protected material without ever being certified as an authenticated user. This attack does not rely on prior sessions established by successfully authenticating users, as relied upon for the "Exploitation of Session Variables, Resource IDs and other Trusted Credentials" attack patterns.
  • Exploiting Trust in Client (aka Make the Client Invisible)
    An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
  • Utilizing REST's Trust in the System Resource to Register Man in the Middle
    This attack utilizes a REST(REpresentational State Transfer)-style applications' trust in the system resources and environment to place man in the middle once SSL is terminated. Rest applications premise is that they leverage existing infrastructure to deliver web services functionality. An example of this is a Rest application that uses HTTP Get methods and receives a HTTP response with an XML document. These Rest style web services are deployed on existing infrastructure such as Apache and IIS web servers with no SOAP stack required. Unfortunately from a security standpoint, there frequently is no interoperable identity security mechanism deployed, so Rest developers often fall back to SSL to deliver security. In large data centers, SSL is typically terminated at the edge of the network - at the firewall, load balancer, or router. Once the SSL is terminated the HTTP request is in the clear (unless developers have hashed or encrypted the values, but this is rare). The attacker can utilize a sniffer such as Wireshark to snapshot the credentials, such as username and password that are passed in the clear once SSL is terminated. Once the attacker gathers these credentials, they can submit requests to the web service provider just as authorized user do. There is not typically an authentication on the client side, beyond what is passed in the request itself so once this is compromised, then this is generally sufficient to compromise the service's authentication scheme.
  • Man in the Middle Attack
    This type of attack targets the communication between two components (typically client and server). The attacker places himself in the communication channel between the two components. Whenever one component attempts to communicate with the other (data flow, authentication challenges, etc.), the data first goes to the attacker, who has the opportunity to observe or alter it, and it is then passed on to the other component as if it was never intercepted. This interposition is transparent leaving the two compromised components unaware of the potential corruption or leakage of their communications. The potential for Man-in-the-Middle attacks yields an implicit lack of trust in communication or identify between two components.

Nessus

  • 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+".");
  • NASL familyMisc.
    NASL idOPENSSH_231.NASL
    descriptionAccording to its banner, the remote host is running OpenSSH 2.3.1. This version is vulnerable to a flaw that allows any attacker who can obtain the public key of a valid SSH user to log into this host without any authentication.
    last seen2020-06-01
    modified2020-06-02
    plugin id10608
    published2001-02-09
    reporterThis script is Copyright (C) 2001-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/10608
    titleOpenSSH 2.3.1 SSHv2 Public Key Authentication Bypass
    code
    #
# (C) Tenable Network Security, Inc.
#


include("compat.inc");

if(description)
{
 script_id(10608);
 script_version ("1.26");
 script_cvs_date("Date: 2018/07/16 14:09:13");

 script_cve_id("CVE-2001-1585");
 script_bugtraq_id(2356);

 script_name(english:"OpenSSH 2.3.1 SSHv2 Public Key Authentication Bypass");
 script_summary(english:"Checks for the remote SSH version");
 
 script_set_attribute(attribute:"synopsis", value:
"The remote host has an application that is affected by a
authentication bypass vulnerability." );
 script_set_attribute(attribute:"description", value:
"According to its banner, the remote host is running OpenSSH 2.3.1.

This version is vulnerable to a flaw that allows any attacker who can
obtain the public key of a valid SSH user to log into this host
without any authentication." );
 script_set_attribute(attribute:"see_also", value:"http://www.openbsd.org/advisories/ssh_bypass.txt" );
 script_set_attribute(attribute:"solution", value:
"Upgrade to OpenSSH 2.3.2." );
 script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
 script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
 script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
 script_set_attribute(attribute:"exploit_available", value:"false");
 script_cwe_id(287);
	
 script_set_attribute(attribute:"plugin_publication_date", value: "2001/02/09");
 script_set_attribute(attribute:"vuln_publication_date", value: "2001/02/08");
 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) 2001-2018 Tenable Network Security, Inc.");
 script_family(english:"Misc.");

 script_dependencie("ssh_detect.nasl");
 script_require_ports("Services/ssh", 22);
 exit(0);
}

include("backport.inc");
include("global_settings.inc");
include("misc_func.inc");

# Ensure the port is open.
port = get_service(svc:"ssh", exit_on_fail:TRUE);

# Get banner for service.
banner = get_kb_item_or_exit("SSH/banner/"+port);

bp_banner = tolower(get_backport_banner(banner:banner));
if ("openssh" >!< bp_banner) exit(0, "The SSH service on port "+port+" is not OpenSSH.");
if (backported) exit(1, "The banner from the OpenSSH server on port "+port+" indicates patches may have been backported.");

if (ereg(pattern:"openssh[-_]2\.3\.1([^0-9]|$)", string:bp_banner))
  security_hole(port);

References