Vulnerabilities > CVE-2015-6298 - OS Command Injection vulnerability in Cisco web Security Appliance 8.5.0497

047910
CVSS 9.0 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
SINGLE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
network
low complexity
cisco
CWE-78
critical
nessus

Summary

The admin web interface in Cisco AsyncOS 8.x before 8.0.8-113, 8.1.x and 8.5.x before 8.5.3-051, 8.6.x and 8.7.x before 8.7.0-171-LD, and 8.8.x before 8.8.0-085 on Web Security Appliance (WSA) devices allows remote authenticated users to obtain root privileges via crafted certificate-generation arguments, aka Bug ID CSCus83445.

Vulnerable Configurations

Part Description Count
Application
Cisco
1

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-20151104-AOS_WSA.NASL
descriptionAccording to its self-reported version, the Cisco Web Security Appliance (WSA) running on the remote host is affected by the following vulnerabilities : - A denial of service vulnerability exists due to a failure to free memory objects when retrieving data from the proxy server to terminate a TCP connection. An unauthenticated, remote attacker can exploit this, by opening a large number of proxy connections, to cause exhaustion of memory, resulting in the WSA to stop passing traffic. (CVE-2015-6292) - A denial of service vulnerability exists due to a failure to free memory when a file range is requested. An unauthenticated, remote attacker can exploit this, by opening multiple connections that request file ranges, to cause exhaustion of memory, resulting in the WSA to stop passing traffic. (CVE-2015-6293) - A flaw exists in the certificate generation process due to improper validation of parameters passed to the affected scripts of the web interface. An authenticated, remote attacker can exploit this, via crafted arguments to the parameters, to execute arbitrary commands on the system with root level privileges. (CVE-2015-6298) - A denial of service vulnerability exists due to improper handling of TCP packets sent at a high rate. An unauthenticated, remote attacker can exploit this to exhaust all available memory, preventing any more TCP connections from being accepted. (CVE-2015-6321)
last seen2020-03-17
modified2015-11-18
plugin id86916
published2015-11-18
reporterThis script is Copyright (C) 2015-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/86916
titleCisco Web Security Appliance Multiple Vulnerabilities
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(86916);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/28");

  script_cve_id(
    "CVE-2015-6292",
    "CVE-2015-6293",
    "CVE-2015-6298",
    "CVE-2015-6321"
  );
  script_xref(name:"CISCO-BUG-ID", value:"CSCzv95795");
  script_xref(name:"CISCO-BUG-ID", value:"CSCus83445");
  script_xref(name:"CISCO-BUG-ID", value:"CSCus10922");
  script_xref(name:"CISCO-BUG-ID", value:"CSCur39155");
  script_xref(name:"CISCO-BUG-ID", value:"CSCuu29304");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20151104-aos");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20151104-wsa");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20151104-wsa1");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20151104-wsa2");

  script_name(english:"Cisco Web Security Appliance Multiple Vulnerabilities");
  script_summary(english:"Checks the WSA version.");

  script_set_attribute(attribute:"synopsis", value:
"The remote security appliance is missing a vendor-supplied patch.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version, the Cisco Web Security
Appliance (WSA) running on the remote host is affected by the
following vulnerabilities :

  - A denial of service vulnerability exists due to a
    failure to free memory objects when retrieving data from
    the proxy server to terminate a TCP connection. An
    unauthenticated, remote attacker can exploit this, by
    opening a large number of proxy connections, to cause
    exhaustion of memory, resulting in the WSA to stop
    passing traffic. (CVE-2015-6292)

  - A denial of service vulnerability exists due to a
    failure to free memory when a file range is requested.
    An unauthenticated, remote attacker can exploit this, by
    opening multiple connections that request file ranges,
    to cause exhaustion of memory, resulting in the WSA to
    stop passing traffic. (CVE-2015-6293)

  - A flaw exists in the certificate generation process due
    to improper validation of parameters passed to the
    affected scripts of the web interface. An authenticated,
    remote attacker can exploit this, via crafted arguments
    to the parameters, to execute arbitrary commands on the
    system with root level privileges. (CVE-2015-6298)

  - A denial of service vulnerability exists due to improper
    handling of TCP packets sent at a high rate. An
    unauthenticated, remote attacker can exploit this to
    exhaust all available memory, preventing any more
    TCP connections from being accepted. (CVE-2015-6321)");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151104-aos
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?561dad7b");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151104-wsa
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9afe6628");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151104-wsa1
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?8b233cd4");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151104-wsa2
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6af33d45");
  script_set_attribute(attribute:"solution", value:
"Apply the relevant updates referenced in Cisco Security Advisories
cisco-sa-20151104-aos, cisco-sa-20151104-wsa, cisco-sa-20151104-wsa1,
and cisco-sa-20151104-wsa2.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/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_set_attribute(attribute:"vuln_publication_date", value:"2015/11/04");
  script_set_attribute(attribute:"patch_publication_date", value:"2015/11/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/11/18");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/h:cisco:web_security_appliance");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2015-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("cisco_wsa_version.nasl");
  script_require_keys("Host/AsyncOS/Cisco Web Security Appliance/DisplayVersion", "Host/AsyncOS/Cisco Web Security Appliance/Version");

  exit(0);
}

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

display_ver = get_kb_item_or_exit('Host/AsyncOS/Cisco Web Security Appliance/DisplayVersion');
ver = get_kb_item_or_exit('Host/AsyncOS/Cisco Web Security Appliance/Version');

if (ver =~ "^[0-6]\." || ver =~ "^7\.[0-6]\.") # Prior to 7.7
  display_fix = '7.7.0-761';
else if (ver =~ "^7\.7\.")
  display_fix = '7.7.0-761';
else if (ver =~ "^8\.0\.")
  display_fix = '8.0.8-113';
else if (ver =~ "^8\.1\.")
  display_fix = '8.5.3-051';
else if (ver =~ "^8\.5\.")
  display_fix = '8.5.3-051';
else if (ver =~ "^8\.6\.")
  display_fix = '8.7.0-171';
else if (ver =~ "^8\.7\.")
  display_fix = '8.7.0-171';
else if (ver =~ "^8\.8\.")
  display_fix = '8.8.0-085';
else
  audit(AUDIT_INST_VER_NOT_VULN, 'Cisco WSA', display_ver);

fix = str_replace(string:display_fix, find:'-', replace:'.');

if (ver_compare(ver:ver, fix:fix, strict:FALSE) == -1)
{
  if (report_verbosity > 0)
  {
    report =
      '\n  Installed version : ' + display_ver +
      '\n  Fixed version     : ' + display_fix +
      '\n';
    security_hole(port:0, extra:report);
  }
  else security_hole(0);
  exit(0);
}
else audit(AUDIT_INST_VER_NOT_VULN, 'Cisco WSA', display_ver);