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Citrix Releases Security Update for Log4j2 Vulnerabilities

Citrix has released a security advisory about Log4j2 vulnerabilities in Citrix Endpoint Management and Citrix Virtual Apps and Desktops.

Threat ID:
CC-4003
Threat Severity:
Information only
Published:
5 January 2022 3:20 PM
Report a cyber attack: call 0300 303 5222 or email [email protected]

Summary

Citrix has released a security advisory about Log4j2 vulnerabilities in Citrix Endpoint Management and Citrix Virtual Apps and Desktops.

Threat details

Introduction

Citrix has released and updated their advisory to address the Log4Shell vulnerabilities in Citrix Endpoint Management (Citrix XenMobile Server) and Citrix Virtual Apps and Desktops (XenApp & XenDesktop). An unauthenticated remote attacker could exploit these vulnerabilities to execute arbitrary code, cause a denial-of-service, and take control of affected systems.

NHS Digital response to Log4Shell

This alert is part of NHS Digital's wider response to the Log4Shell remote code execution vulnerability. For more information on Log4Shell itself, please visit our cyber alerts article Log4Shell RCE Vulnerability CC-3989.
 

Additional Citrix systems may be vulnerable and affected organisations should regularly review the Citrix Security Advisory for CVE-2021-44228, CVE-2021-45046, CVE-2021-45105 and CVE-2021-44832. NHS and social care organisations are invited to use the Cyber Associates Network to find out additional information and participate in discussion about the Log4Shell remote code execution vulnerability and affected Citrix products.

Remediation advice

Affected organisations are encouraged to review the Citrix Security Advisory CTX335705 and review the Citrix support articles below and apply any necessary updates or workarounds.

Remediation steps

Type Step
Patch

XenMobile Server 10.14 RP2 | CTX335763


https://support.citrix.com/article/CTX335763
Patch

XenMobile Server 10.14 RP3 | CTX335897


https://support.citrix.com/article/CTX335897
Patch

XenMobile Server 10.13 RP5 |CTX335753


https://support.citrix.com/article/CTX335753
Patch

XenMobile Server 10.13 RP6 |CTX335875


https://support.citrix.com/article/CTX335875
Patch

XenMobile Server 10.12 RP10 | CTX335785


https://support.citrix.com/article/CTX335785
Patch

XenMobile Server 10.12 RP11 | CTX335861


https://support.citrix.com/article/CTX335861
Patch

Citrix Virtual Apps and Desktops (XenApp & XenDesktop)


https://support.citrix.com/article/CTX335705

CVE Vulnerabilities

Status Published

CVE-2021-44228

Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.
Status Published

CVE-2021-44832

Apache Log4j2 versions 2.0-beta7 through 2.17.0 (excluding security fix releases 2.3.2 and 2.12.4) are vulnerable to a remote code execution (RCE) attack when a configuration uses a JDBC Appender with a JNDI LDAP data source URI when an attacker has control of the target LDAP server. This issue is fixed by limiting JNDI data source names to the java protocol in Log4j2 versions 2.17.1, 2.12.4, and 2.3.2.
Status Published

CVE-2021-45046

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.
Status Published

CVE-2021-45105

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0, 2.12.3, and 2.3.1.

Last edited: 5 January 2022 3:20 pm