VMware urges to patch VMware Horizon servers against Log4j attacks
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-2021-45046 | Remote Code Execution in Apache Log4j2 via Incomplete Log4Shell Fix CVE-2021-45046 is a remote code execution and information disclosure flaw in Apache Log4j2 (CWE-917) that resulted from an incomplete fix to CVE-2021-44228 (Log4Shell), leaving the Thread Context Lookup Pattern vulnerable in certain non-default configurations. It is triggered when an application logs attacker-controlled data using layouts or patterns that perform Thread Context (MDC) lookups, allowing crafted lookup expressions to be evaluated against untrusted input. A successful attacker can achieve remote code execution, or potentially information disclosure, on the affected service. Any deployment of Apache Log4j2 that relies on the affected non-default lookup configurations is exposed, which given Log4j2's ubiquity in Java applications and embedded products means a very large installed base. Exploitation is confirmed: the flaw is in CISA KEV (added 2023-05-01) with known ransomware use, and EPSS assigns a 100% probability of exploitation within 30 days. Do: Upgrade Log4j2 to 2.17.0 or later per vendor instructions (or 2.12.3/2.3.1 for the legacy 2.12/2.3 branches), since the 2.16.0 fix was itself incomplete in some non-default configurations. Where upgrading is not immediately possible, remove the JndiLookup class from the Log4j2 jar or disable lookup processing, and audit applications and dependencies that bundle Log4j2 while following the CISA KEV required action to apply vendor updates. | 9.0 | 100% | KEV ransomware |
| massmillions of Java deployments worldwide, with hundreds of thousands of internet-exposed services observed in public scans during the Log4Shell campaign |
Full article710 words · extracted from securityaffairs.com · click to collapse
VMware released security patches to address critical Log4j security vulnerabilities in VMware Horizon servers targeted in ongoing attacks.
VMware urges customers to patch critical Log4j security vulnerabilities impacting Internet-exposed VMware Horizon servers targeted in ongoing attacks.
Searching for Internet-exposed VMware Horizon servers with Shodan, we can find tens of thousands of installs potentially exposed to attacks.
This month, the Night Sky ransomware operation started exploiting the Log4Shell flaw (CVE-2021-44228) in the Log4j library to gain access to VMware Horizon systems.
In early January, threat actors started targeting VMware Horizon systems exposed on the Internet. VMware has addressed Log4Shell in Horizon with the release of 2111, 7.13.1, 7.10.3 versions, but unfortunately many unpatched systems are still exposed online.
https://twitter.com/GossiTheDog/status/1484145056198053891
Recently, Microsoft posted a warning about a new campaign from a China-based actor it tracks as DEV-0401 to exploit the Log4Shell vulnerability on VMware Horizon systems exposed on the internet, and deploy Night Sky ransomware.
We have observed a China-based ransomware operator that we’re tracking as DEV-0401 exploiting the CVE-2021-44228 vulnerability in Log4j 2 (aka #log4shell) targeting internet-facing systems running VMWare Horizon. https://t.co/6GOdRwRTjk
— Microsoft Threat Intelligence (@MsftSecIntel) January 11, 2022
The security team at the UK National Health Service (NHS) also announced to have spotted threat actors exploiting the Log4Shell vulnerability to hack VMWare Horizon servers and install web shells.
“An unknown threat group has been observed targeting VMware Horizon servers running versions affected by Log4Shell vulnerabilities in order to establish persistence within affected networks.” reads the security advisory published by NHS.
“The attack likely consists of a reconnaissance phase, where the attacker uses theJava Naming and Directory InterfaceTM (JNDI) via Log4Shell payloads to call back to malicious infrastructure. Once a weakness has been identified, the attack then uses the Lightweight Directory Access Protocol (LDAP) to retrieve and execute a malicious Java class file that injects a web shell into the VM Blast Secure Gateway service.”
Once installed a web shell, threat actors can use it to carry out a broad range of malicious activities, such as deploying data exfiltration or deployment of ransomware.
Upon exploiting log4J flaws, threat actors deploy custom web shells into the VM Blast Secure Gateway service to gain access to the networks of target organizations.
In an email to Bleeping Computer today, VMware said they are strongly urging customers to patch their Horizon servers to defend against these active attacks.
Multiple VMWare products, including VMware Horizon products, are impacted by remote code execution vulnerabilities via Apache Log4j (CVE-2021-44228, CVE-2021-45046).
Recently the Dutch National Cybersecurity Centre (NCSC) warned organizations to remain vigilant on possible attacks exploiting the Log4J vulnerability. According to the Dutch agency, threat actors the NCSC will continue to attempt to exploit the Log4Shell flaw in future attacks.
“Partly due to the rapid actions of many organizations, the extent of active abuse appears to be not too bad at the moment. But that doesn’t mean it stops there. It is expected that malicious parties will continue to search for vulnerable systems and carry out targeted attacks in the coming period. It is therefore important to remain vigilant.” states the Dutch NCSC agency. “The NCSC advises organizations to continue to monitor whether vulnerable systems are used and to apply updates or mitigating measures where necessary. In addition, the NCSC advises directors to stay alert by informing themselves about Log4j and the possible impact of abuse on business continuity.”
The risk that cybercriminal groups and nation-state actors could exploit Log4j vulnerabilities in future attacks is still high.
The virtualization giant urges customers to examine VMSA-2021-0028 and apply the guidance for Horizon. VMware published a dedicated Guidance to VMware Horizon customers regarding Log4j.
“In a zero-day situation such as the Apache Software Foundation Log4j vulnerability, cyber criminals are racing to exploit the vulnerabilities identified by CVE-2021-44228 and CVE-2021-45046 before organizations can address them. We continue to amplify the message in our security advisory, VMSA-2021-0028, urging customers to address the vulnerability immediately, including with VMware Horizon 8 and Horizon 7.x.” reads the guidance. “While most customers have followed the guidance, those who have not done so remain at risk.”
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