Vulnerabilities > CVE-2019-6639 - Cross-site Scripting vulnerability in F5 Big-Ip Advanced Firewall Manager

047910
CVSS 4.8 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
HIGH
Confidentiality impact
LOW
Integrity impact
LOW
Availability impact
NONE
network
low complexity
f5
CWE-79
nessus

Summary

On BIG-IP (AFM, PEM) 14.1.0-14.1.0.5, 14.0.0-14.0.0.4, 13.0.0-13.1.1.4, 12.1.0-12.1.4, 11.6.1-11.6.3.4, and 11.5.1-11.5.8, an undisclosed TMUI pages for AFM and PEM Subscriber management are vulnerable to a stored cross-site scripting (XSS) issue. This is a control plane issue only and is not accessible from the data plane. The attack requires a malicious resource administrator to store the XSS.

Vulnerable Configurations

Part Description Count
Application
F5
174

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Embedding Scripts in Non-Script Elements
    This attack is a form of Cross-Site Scripting (XSS) where malicious scripts are embedded in elements that are not expected to host scripts such as image tags (<img>), comments in XML documents (< !-CDATA->), etc. These tags may not be subject to the same input validation, output validation, and other content filtering and checking routines, so this can create an opportunity for an attacker to tunnel through the application's elements and launch a XSS attack through other elements. As with all remote attacks, it is important to differentiate the ability to launch an attack (such as probing an internal network for unpatched servers) and the ability of the remote attacker to collect and interpret the output of said attack.
  • Embedding Scripts within Scripts
    An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute scripts. The attacker leverages this capability to execute scripts to execute his/her own script by embedding it within other scripts that the target software is likely to execute. The attacker must have the ability to inject script into script that is likely to be executed. If this is done, then the attacker can potentially launch a variety of probes and attacks against the web server's local environment, in many cases the so-called DMZ, back end resources the web server can communicate with, and other hosts. With the proliferation of intermediaries, such as Web App Firewalls, network devices, and even printers having JVMs and Web servers, there are many locales where an attacker can inject malicious scripts. Since this attack pattern defines scripts within scripts, there are likely privileges to execute said attack on the host. Of course, these attacks are not solely limited to the server side, client side scripts like Ajax and client side JavaScript can contain malicious scripts as well. In general all that is required is for there to be sufficient privileges to execute a script, but not protected against writing.
  • Cross-Site Scripting in Error Pages
    An attacker distributes a link (or possibly some other query structure) with a request to a third party web server that is malformed and also contains a block of exploit code in order to have the exploit become live code in the resulting error page. When the third party web server receives the crafted request and notes the error it then creates an error message that echoes the malformed message, including the exploit. Doing this converts the exploit portion of the message into to valid language elements that are executed by the viewing browser. When a victim executes the query provided by the attacker the infected error message error message is returned including the exploit code which then runs in the victim's browser. XSS can result in execution of code as well as data leakage (e.g. session cookies can be sent to the attacker). This type of attack is especially dangerous since the exploit appears to come from the third party web server, who the victim may trust and hence be more vulnerable to deception.
  • Cross-Site Scripting Using Alternate Syntax
    The attacker uses alternate forms of keywords or commands that result in the same action as the primary form but which may not be caught by filters. For example, many keywords are processed in a case insensitive manner. If the site's web filtering algorithm does not convert all tags into a consistent case before the comparison with forbidden keywords it is possible to bypass filters (e.g., incomplete black lists) by using an alternate case structure. For example, the "script" tag using the alternate forms of "Script" or "ScRiPt" may bypass filters where "script" is the only form tested. Other variants using different syntax representations are also possible as well as using pollution meta-characters or entities that are eventually ignored by the rendering engine. The attack can result in the execution of otherwise prohibited functionality.

Nessus

NASL familyF5 Networks Local Security Checks
NASL idF5_BIGIP_SOL61002104.NASL
descriptionUndisclosed TMUI pages for AFM and PEM Subscriber management are vulnerable to a stored cross-site scripting (XSS) issue. This is a control plane issue only and is not accessible from the data plane. The attack requires a malicious resource administrator to store the XSS. (CVE-2019-6639) Impact A malicious, authenticated user with Resource Administrator privileges may be able to exploit this vulnerability to allow another user with Administrator privileges to execute system commands. When the BIG-IP system operates in Appliance mode, the vulnerability still exists; however, an attacker cannot force arbitrary system commands because Advanced Shell ( bash ) access is disabled in Appliance mode. Without Appliance mode, arbitrary command execution is possible when exploiting this vulnerability. This issue exists only in the control plane and is not accessible from the data plane. The attack requires a malicious, authenticated user with Resource Administrator privileges to store the XSS.
last seen2020-06-01
modified2020-06-02
plugin id126404
published2019-07-02
reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/126404
titleF5 Networks BIG-IP : BIG-IP AFM and PEM TMUI XSS vulnerability (K61002104)
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from F5 Networks BIG-IP Solution K61002104.
#
# The text description of this plugin is (C) F5 Networks.
#

include("compat.inc");

if (description)
{
  script_id(126404);
  script_version("1.3");
  script_cvs_date("Date: 2020/01/08");

  script_cve_id("CVE-2019-6639");

  script_name(english:"F5 Networks BIG-IP : BIG-IP AFM and PEM TMUI XSS vulnerability (K61002104)");
  script_summary(english:"Checks the BIG-IP version.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote device is missing a vendor-supplied security patch."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Undisclosed TMUI pages for AFM and PEM Subscriber management are
vulnerable to a stored cross-site scripting (XSS) issue. This is a
control plane issue only and is not accessible from the data plane.
The attack requires a malicious resource administrator to store the
XSS. (CVE-2019-6639)

Impact

A malicious, authenticated user with Resource Administrator privileges
may be able to exploit this vulnerability to allow another user with
Administrator privileges to execute system commands. When the BIG-IP
system operates in Appliance mode, the vulnerability still exists;
however, an attacker cannot force arbitrary system commands because
Advanced Shell ( bash ) access is disabled in Appliance mode. Without
Appliance mode, arbitrary command execution is possible when
exploiting this vulnerability. This issue exists only in the control
plane and is not accessible from the data plane. The attack requires a
malicious, authenticated user with Resource Administrator privileges
to store the XSS."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://support.f5.com/csp/article/K61002104"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade to one of the non-vulnerable versions listed in the F5
Solution K61002104."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:S/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N");
  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:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_advanced_firewall_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_policy_enforcement_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/h:f5:big-ip");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/07/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/07/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/07/02");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"F5 Networks Local Security Checks");

  script_dependencies("f5_bigip_detect.nbin");
  script_require_keys("Host/local_checks_enabled", "Host/BIG-IP/hotfix", "Host/BIG-IP/modules", "Host/BIG-IP/version", "Settings/ParanoidReport");

  exit(0);
}


include("f5_func.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
version = get_kb_item("Host/BIG-IP/version");
if ( ! version ) audit(AUDIT_OS_NOT, "F5 Networks BIG-IP");
if ( isnull(get_kb_item("Host/BIG-IP/hotfix")) ) audit(AUDIT_KB_MISSING, "Host/BIG-IP/hotfix");
if ( ! get_kb_item("Host/BIG-IP/modules") ) audit(AUDIT_KB_MISSING, "Host/BIG-IP/modules");

sol = "K61002104";
vmatrix = make_array();

if (report_paranoia < 2) audit(AUDIT_PARANOID);

# AFM
vmatrix["AFM"] = make_array();
vmatrix["AFM"]["affected"  ] = make_list("14.0.0-14.1.0","13.0.0-13.1.1","12.1.0-12.1.4","11.6.0-11.6.3","11.5.0-11.5.8");
vmatrix["AFM"]["unaffected"] = make_list("14.1.0.6","14.0.0.5","13.1.1.5","12.1.4.1","11.6.4","11.5.9");

# PEM
vmatrix["PEM"] = make_array();
vmatrix["PEM"]["affected"  ] = make_list("14.0.0-14.1.0","13.0.0-13.1.1","12.1.0-12.1.4","11.6.0-11.6.3","11.5.0-11.5.8");
vmatrix["PEM"]["unaffected"] = make_list("14.1.0.6","14.0.0.5","13.1.1.5","12.1.4.1","11.6.4","11.5.9");


if (bigip_is_affected(vmatrix:vmatrix, sol:sol))
{
  set_kb_item(name:'www/0/XSS', value:TRUE);
  if (report_verbosity > 0) security_note(port:0, extra:bigip_report_get());
  else security_note(0);
  exit(0);
}
else
{
  tested = bigip_get_tested_modules();
  audit_extra = "For BIG-IP module(s) " + tested + ",";
  if (tested) audit(AUDIT_INST_VER_NOT_VULN, audit_extra, version);
  else audit(AUDIT_HOST_NOT, "running any of the affected modules AFM / PEM");
}