Vulnerabilities > CVE-2018-0224 - OS Command Injection vulnerability in Cisco Staros 21.3.0.67664/21.5.0

047910
CVSS 7.2 - HIGH
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
local
low complexity
cisco
CWE-78
nessus

Summary

A vulnerability in the CLI of the Cisco StarOS operating system for Cisco ASR 5000 Series Aggregation Services Routers could allow an authenticated, local attacker to execute arbitrary commands with root privileges on an affected operating system. The vulnerability is due to insufficient validation of user-supplied input by the affected operating system. An attacker could exploit this vulnerability by authenticating to an affected system and injecting malicious arguments into a vulnerable CLI command. A successful exploit could allow the attacker to execute arbitrary commands with root privileges on the affected system. Cisco Bug IDs: CSCvg38807.

Vulnerable Configurations

Part Description Count
OS
Cisco
2
Hardware
Cisco
3

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
  • Command Delimiters
    An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or a blacklist input validation, as opposed to whitelist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or blacklist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on.
  • Exploiting Multiple Input Interpretation Layers
    An attacker supplies the target software with input data that contains sequences of special characters designed to bypass input validation logic. This exploit relies on the target making multiples passes over the input data and processing a "layer" of special characters with each pass. In this manner, the attacker can disguise input that would otherwise be rejected as invalid by concealing it with layers of special/escape characters that are stripped off by subsequent processing steps. The goal is to first discover cases where the input validation layer executes before one or more parsing layers. That is, user input may go through the following logic in an application: In such cases, the attacker will need to provide input that will pass through the input validator, but after passing through parser2, will be converted into something that the input validator was supposed to stop.
  • Argument Injection
    An attacker changes the behavior or state of a targeted application through injecting data or command syntax through the targets use of non-validated and non-filtered arguments of exposed services or methods.
  • OS Command Injection
    In this type of an attack, an adversary injects operating system commands into existing application functions. An application that uses untrusted input to build command strings is vulnerable. An adversary can leverage OS command injection in an application to elevate privileges, execute arbitrary commands and compromise the underlying operating system.

Nessus

NASL familyCISCO
NASL idCISCO-SA-20180117-STAROS.NASL
descriptionAccording to its self-reported version and model number, the remote Cisco ASR device is affected by multiple command injection vulnerabilities due to improper validation of user input. An authenticated local attacker, using command arguments, could potentially execute arbitrary commands with root privileges.
last seen2020-06-01
modified2020-06-02
plugin id107095
published2018-03-02
reporterThis script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/107095
titleCisco ASR StarOS Multiple CLI Command Injection Vulnerabilities (cisco-sa-20180117-staros / cisco-sa-20180307-staros / cisco-sa-20180307-staros1)
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(107095);
  script_version("1.6");
  script_cvs_date("Date: 2018/07/06 11:26:06");

  script_cve_id("CVE-2018-0115", "CVE-2018-0217", "CVE-2018-0224");
  script_bugtraq_id(102788, 103344, 103346);
  script_xref(name:"CISCO-BUG-ID", value:"CSCvf93332");
  script_xref(name:"CISCO-BUG-ID", value:"CSCvg29441");
  script_xref(name:"CISCO-BUG-ID", value:"CSCvg38807");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20180117-staros");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20180307-staros");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20180307-staros1");

  script_name(english:"Cisco ASR StarOS Multiple CLI Command Injection Vulnerabilities (cisco-sa-20180117-staros / cisco-sa-20180307-staros / cisco-sa-20180307-staros1)");
  script_summary(english:"Checks the StarOS version.");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is affected by multiple command injection
vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version and model number, the remote
Cisco ASR device is affected by multiple command injection
vulnerabilities due to improper validation of user input. An
authenticated local attacker, using command arguments, could
potentially execute arbitrary commands with root privileges.");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180117-staros
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?5aae5b06");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180307-staros
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?a2d6f9a1");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180307-staros1
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?0c6ab9fa");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvf93332");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvg29441");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvg38807");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco bug ID
CSCvf93332, CSCvg29441, or CSCvg38807.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  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:H/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  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:"2018/01/17");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/01/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/03/02");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:staros");
  script_set_attribute(attribute:"cpe", value:"cpe:/h:cisco:asr_5000");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:cisco:asr_5000_series_software");
  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_end_attributes();

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

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

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/Cisco/ASR/Model", "Host/Cisco/StarOS", "Settings/ParanoidReport");
  exit(0);
}

include("audit.inc");
include("cisco_func.inc");
include("cisco_kb_cmd_func.inc");

get_kb_item_or_exit("Host/Cisco/StarOS");

version  = get_kb_item_or_exit("Host/Cisco/StarOS/Version");
model   = get_kb_item_or_exit("Host/Cisco/ASR/Model");

major = NULL;
build = NULL;
fix = NULL;
train = NULL;

# only affects ASR 5000/5500/5700 series systems
if (model !~ "^50\d{2}$")
  audit(AUDIT_DEVICE_NOT_VULN, 'The ASR ' + model);

# Normalize train characters
version= toupper(version);

# For newer versions, We may be able to get the build number during detection
build = get_kb_item("Host/Cisco/StarOS/Build");
if (!empty_or_null(build))
  version += "." + build;

# defensive check for the pregmatches below
if (version !~ "^[\d\.]+\([\d\.]+" &&
    version !~ "^[\d\.]+([A-Z]{1,2}\d+)?\.\d+$")
  audit(AUDIT_VER_FORMAT, version);

if (report_paranoia < 2) audit(AUDIT_PARANOID);

# old style of versioning 15.0(5439), style change mid 16.1, making
# all of the old style versions fall into the vulnerable range.
if ("(" >< version)
{
  major = pregmatch(pattern:"^([\d\.]+)\(", string:version);

  if(!isnull(major))
  {
    major = major[1];

    if (isnull(build))
    {
      build = pregmatch(pattern:"^[\d\.]+\(([\d\.]+)", string:version);
      if(!isnull(build))
      {
        build = build[1];

        # Set the train to an empty string, or it causes issues when
        # seeing if a patched version exists using NULL as the value
        train = '';
      }
      else
        exit(1, "Unable to extract build number.");
    }
  }
  else
    exit(1, "Unable to extract version number.");
}
else
{
  # extract major, train, and build for new style
  extract = pregmatch(pattern:"^([\d\.]+)\.([A-Z]{1,2}\d+)?\.?(\d+)?", string:version);
  if (!isnull(extract))
  {
    major = extract[1];
    train = extract[2];
    if (isnull(build))
      build = extract[3];
  }
}

# Defensive checking for versions that we haven't yet seen
if(empty_or_null(major) || empty_or_null(build))
  exit(1, "An error occurred during version extraction.");

fix_array = make_array(
  "21.4", make_array("C0", 68040, "D0", 68036, "M0", 68033),
  "21.5", make_array("C0", 68318, "M0", 68317),
  "21.6", make_array("A0", 68321, "D0", 68319, "RU0", 68455),
  "21.7", make_array("D0", 68717, "M0", 68711)
);

if (major == "21.3.5" && int(build) < 68140)
  fix = "21.3.5.68140";
else if (major == "21.4.0" && int(build) < 68051)
  fix = "21.4.0.68051";
else if (major == "21.5.0" && int(build) < 68363)
  fix = "21.5.0.68363";
else if (major == "21.7.0" && int(build) < 68846)
  fix = "21.7.0.68846";
else if (!empty_or_null(fix_array[major]) &&
         !empty_or_null(train) &&
         int(build) < fix_array[major][train])
  fix = major + "." + train + "." + fix_array[major][train];

if (fix)
{
  security_report_cisco(
    port     : 0,
    severity : SECURITY_HOLE,
    override : TRUE,
    version  : version,
    fix      : fix,
    bug_id   : 'CSCvf93332, CSCvg29441, or CSCvg38807'
  );
}
else audit(AUDIT_DEVICE_NOT_VULN, "ASR " + model, version);