Vulnerabilities > CVE-2020-5877 - Improper Input Validation vulnerability in F5 products

047910
CVSS 5.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
PARTIAL
network
low complexity
f5
CWE-20
nessus

Summary

On BIG-IP 15.0.0-15.1.0.1, 14.1.0-14.1.2.3, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.1, malformed input to the DATAGRAM::tcp iRules command within a FLOW_INIT event may lead to a denial of service.

Vulnerable Configurations

Part Description Count
Application
F5
1107

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • 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.
  • 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.

Nessus

NASL familyF5 Networks Local Security Checks
NASL idF5_BIGIP_SOL54200228.NASL
descriptionMalformed input to the DATAGRAM::tcp iRules command within a FLOW_INIT event may lead to a denial of service. (CVE-2020-5877) Impact Remote attackers may be able to perform a denial-of-service (DoS) attack on the BIG-IP system.
last seen2020-05-12
modified2020-04-30
plugin id136140
published2020-04-30
reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/136140
titleF5 Networks BIG-IP : BIG-IP iRules vulnerability (K54200228)
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from F5 Networks BIG-IP Solution K54200228.
#
# The text description of this plugin is (C) F5 Networks.
#

include("compat.inc");

if (description)
{
  script_id(136140);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/07/09");

  script_cve_id("CVE-2020-5877");

  script_name(english:"F5 Networks BIG-IP : BIG-IP iRules vulnerability (K54200228)");
  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:
"Malformed input to the DATAGRAM::tcp iRules command within a FLOW_INIT
event may lead to a denial of service. (CVE-2020-5877)

Impact

Remote attackers may be able to perform a denial-of-service (DoS)
attack on the BIG-IP system."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://support.f5.com/csp/article/K54200228"
  );
  script_set_attribute(
    attribute:"solution",
    value:
"Upgrade to one of the non-vulnerable versions listed in the F5
Solution K54200228."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  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:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-5877");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_access_policy_manager");
  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_application_acceleration_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_application_security_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_application_visibility_and_reporting");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_global_traffic_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_link_controller");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_local_traffic_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:"2020/04/30");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/04/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/04/30");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 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");

  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 = "K54200228";
vmatrix = make_array();

# AFM
vmatrix["AFM"] = make_array();
vmatrix["AFM"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["AFM"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");

# AM
vmatrix["AM"] = make_array();
vmatrix["AM"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["AM"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");

# APM
vmatrix["APM"] = make_array();
vmatrix["APM"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["APM"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");

# ASM
vmatrix["ASM"] = make_array();
vmatrix["ASM"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["ASM"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");

# AVR
vmatrix["AVR"] = make_array();
vmatrix["AVR"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["AVR"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");

# GTM
vmatrix["GTM"] = make_array();
vmatrix["GTM"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["GTM"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");

# LC
vmatrix["LC"] = make_array();
vmatrix["LC"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["LC"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");

# LTM
vmatrix["LTM"] = make_array();
vmatrix["LTM"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["LTM"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");

# PEM
vmatrix["PEM"] = make_array();
vmatrix["PEM"]["affected"  ] = make_list("15.1.0","15.0.0-15.0.0","14.0.0-14.1.2","13.1.0-13.1.3","12.1.0-12.1.5","11.6.1-11.6.5");
vmatrix["PEM"]["unaffected"] = make_list("16.0.0","15.1.0.2","14.1.2.5","13.1.3.4","12.1.5.2","11.6.5.2");


if (bigip_is_affected(vmatrix:vmatrix, sol:sol))
{
  if (report_verbosity > 0) security_warning(port:0, extra:bigip_report_get());
  else security_warning(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");
}