Attackers still exploit Log4Shell on VMware Horizon servers, CISA warns
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2021-44228 | JNDI Injection Remote Code Execution in Apache Log4j2 (Log4Shell) Apache Log4j2, an extremely widely used Java logging library, fails to protect its JNDI lookup feature against attacker-controlled JNDI-related endpoints (CWE-20, CWE-502), so crafted text processed by the logger causes the Java runtime to fetch and load attacker-supplied objects, leading to remote code execution. The flaw is triggered whenever attacker-controlled input reaches the logging API and is parsed for JNDI lookups, a pattern common in web servers and enterprise Java applications that log user-supplied fields such as headers or form values. Successful exploitation yields arbitrary code execution under the privileges of the affected application, giving attackers a foothold for lateral movement, data theft, and ransomware deployment. Any Java application or product that ships or bundles an affected Apache Log4j2 release is exposed, making this one of the most broadly deployed vulnerabilities ever disclosed. Exploitation is confirmed in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2021-12-10 with known ransomware use, and EPSS assigns a 100% probability of exploitation within 30 days. Do: Inventory all Java applications and dependencies for Apache Log4j2 and apply the vendor's patched updates, or remove affected assets from the network, as required by CISA's KEV catalog. Where updates are not yet available, use the temporary mitigations in CISA's ED-22-02 recommended-mitigation guidance, such as disabling message lookups, only until patches are applied. Prioritize internet-facing and business-critical systems and hunt for exploitation activity given known ransomware use. | 10.0 | 100% | KEV ransomware PoC ×9 |
| masshundreds of millions of Java applications/devices, with hundreds of thousands of internet-exposed services | |
| CVE-2022-22954 | Server-Side Template Injection RCE in VMware Workspace ONE Access and Identity Manager CVE-2022-22954 is a server-side template injection vulnerability (CWE-94) in VMware Workspace ONE Access and VMware Identity Manager that allows remote code execution on affected appliances. It is triggered when attacker-controlled input is passed into a server-side template engine, allowing injected template directives to be evaluated and executed as code on the server. A successful attacker gains the ability to run arbitrary code on the identity appliance, and CISA notes the flaw has been used in ransomware campaigns, so compromise can serve as an initial foothold for broader enterprise intrusion. Any organization running Workspace ONE Access or Identity Manager, including deployments where the Identity Manager component is bundled into VMware Horizon environments, is potentially affected, though the source data does not specify affected version ranges. The vulnerability was added to CISA's Known Exploited Vulnerabilities catalog on 2022-04-14 with ransomware use confirmed and a required action to apply vendor updates, and EPSS currently assigns it a 100% probability of exploitation within 30 days (100th percentile); no public PoC is known. Do: Apply the patches published in VMware advisory VMSA-2022-0011 (April 2022) to Workspace ONE Access and Identity Manager appliances as required by the CISA KEV listing, prioritizing internet-facing instances, and restrict or remove public exposure until patched. Review appliance and web-server logs for template-injection probes and unexpected processes spawned by the identity service, and investigate any indications of compromise for follow-on ransomware or lateral-movement activity. | 9.8 | 100% | KEV ransomware PoC |
| large≈ tens of thousands of internet-exposed Workspace ONE Access / Identity Manager instances (order-of-magnitude estimate; exact count unknown) |
Full article504 words · extracted from helpnetsecurity.com · click to collapse
If your organization is running VMware Horizon and Unified Access Gateway servers and you haven’t implemented the patches or workarounds to fix/mitigate the Log4Shell vulnerability (CVE-2021-44228) in December 2021, you should threat all those systems as compromised, the Cybersecurity and Infrastructure Security Agency (CISA) has advised on Thursday.
The agency accompanied the warning with detailed technical information and indicators of compromised related to two separate incident response engagements they and the United States Coast Guard Cyber Command (CGCYBER) have conducted in the past months.
The attacks
Since the public revelation of its existence and first detections of active exploitation in December 2021, attackers have been exploiting Log4Shell in a variety of the many vulnerable IT solutions.
According to the CISA, cyber threat actors, including state-sponsored advanced persistent threat (APT) actors, have continued to exploit Log4Shell in unpatched, internet-facing VMware Horizon and Unified Access Gateway servers to obtain initial access to organizations.
“As part of this exploitation, suspected APT actors implanted loader malware on compromised systems with embedded executables enabling remote command and control (C2). In one confirmed compromise, these APT actors were able to move laterally inside the network, gain access to a disaster recovery network, and collect and exfiltrate sensitive data,” CISA noted, and detailed both engagements – one of which ended up with them discovering that the victim organization was compromised by multiple threat actor groups.
One of these groups also leveraged CVE-2022-22954, a RCE vulnerability in VMware Workspace ONE Access and Identity Manager, to implant a webshell.
Following both compromises, the attackers exfiltrated sensitive data, some from one of the victims’ production environment, and may have gotten their hands on sensitive law enforcement investigation data.
What should you do?
As mentioned before, CISA advises organizations to assume that all their unpatched VMware Horizon and Unified Access Gateway servers are compromised and go from there.
Before cleaning the servers, the agency advises collecting and reviewing relevant logs, data, and artifacts and engaging incident responders to make sure “the actor is eradicated from the network, and avoid residual issues that could enable follow-on exploitation.”
Once that’s done, they should apply the fixes or workarounds, check that no vulnerabilities remain (with a vendor-supplied script), and commit to pushing out updates and patches for all solutions they use more quickly in the future.
“Minimize the internet-facing attack surface by hosting essential services on a segregated demilitarized (DMZ) zone, ensuring strict network perimeter access controls, and implementing regularly updated web application firewalls (WAFs) in front of public-facing services,” CISA also counsels.
“Use best practices for identity and access management (IAM) by implementing multifactor authentication (MFA), enforcing use of strong passwords, and limiting user access through the principle of least privilege.”
It’s also a good idea to find other instances of vulnerable Log4j versions within your environment and start with remediation efforts. You should particularly check solutions that may make good targets for Log4Shell exploitation.
Log4Shell will probably continue to haunt many organizations for years, but yours doesn’t have to be one of them.
Text extracted automatically; images, tables and formatting may be missing. Original: https://www.helpnetsecurity.com/2022/06/24/log4shell-vmware-horizon/