CyberSecBulletin
CVE-2020-8193Exploited in the wildNVD status: Analyzed

Citrix ADC, Gateway, and SD-WAN WANOP Appliance Authorization Bypass

Published Updated By the CyberSecBulletin desk

CVE-2020-8193 is a medium-severity improper authentication vulnerability in Citrix ADC, Citrix Gateway, Citrix SDWAN WAN-OP, with a CVSS 3.1 base score of 6.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Application Delivery Controller Firmware to 10.5-70.18 or 11.1-64.14 or 12.0-63.21 or 12.1-57.18, whichever matches your release line, or a later version.
  2. Update Netscaler Gateway Firmware to 10.5-70.18 or 11.1-64.14 or 12.0-63.21 or 12.1-57.18, whichever matches your release line, or a later version.
  3. Update Gateway Firmware to 13.0-58.30 or a later version.
  4. CISA's required action: Apply updates per vendor instructions.
  5. Read the advisory on support.citrix.com for workarounds and exact fixed builds.
  6. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Citrix ADC, Citrix Gateway, Citrix SDWAN WAN-OPCitrix ADC, Citrix Gateway, Citrix SDWAN WAN-OPNot specified in the recordNot stated
CitrixApplication Delivery Controller Firmware10.5 up to, but not including, 10.5-70.18; 11.1 up to, but not including, 11.1-64.14; 12.0 up to, but not including, 12.0-63.21; 12.1 up to, but not including, 12.1-57.18; 13.0 up to, but not including, 13.0-58.3010.5-70.18, 11.1-64.14, 12.0-63.21, 12.1-57.18, 13.0-58.30
CitrixNetscaler Gateway Firmware10.5 up to, but not including, 10.5-70.18; 11.1 up to, but not including, 11.1-64.14; 12.0 up to, but not including, 12.0-63.21; 12.1 up to, but not including, 12.1-57.1810.5-70.18, 11.1-64.14, 12.0-63.21, 12.1-57.18
CitrixGateway Firmware13.0 up to, but not including, 13.0-58.3013.0-58.30
CitrixSd-wan Wanop10.2 up to, but not including, 10.2.7; 11.0 up to, but not including, 11.0.3d; 11.1 up to, but not including, 11.1.1a10.2.7, 11.0.3d, 11.1.1a

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
LowSome restricted data can be read.
Integrity
LowLimited modification of data is possible.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.16.5MediumNVD
CVSS 3.16.5MediumCISA (ADP)
CVSS 2.05.0MediumNVD

Official description

Improper access control in Citrix ADC and Citrix Gateway versions before 13.0-58.30, 12.1-57.18, 12.0-63.21, 11.1-64.14 and 10.5-70.18 and Citrix SDWAN WAN-OP versions before 11.1.1a, 11.0.3d and 10.2.7 allows unauthenticated access to certain URL endpoints.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

How developers prevent this class of flaw

  • Use an authentication framework or library such as the OWASP ESAPI Authentication feature.

More Improper Authentication vulnerabilities (CWE-287)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: partial).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Technical write-ups (may include proof of concept)

Other vulnerabilities in Citrix ADC, Citrix Gateway, Citrix SDWAN WAN-OP

All Citrix ADC, Citrix Gateway, Citrix SDWAN WAN-OP vulnerabilities

Recent Improper Authentication vulnerabilities

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