Conti ransomware gang exploits Log4Shell bug in its operations
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 |
Full article524 words · extracted from securityaffairs.com · click to collapse
Pierluigi Paganini
December 17, 2021
The Conti ransomware gang is the first ransomware operation exploiting the Log4Shell vulnerability to target VMware vCenter Servers.
Conti ransomware gang is the first professional race that leverages Log4Shell exploit to compromise VMware vCenter Server installs. The ransomware group used the exploit to target internal devices that are not protected.
Conti operators run a private Ransomware-as-a-Service (RaaS), the malware appeared in the threat landscape at the end of December 2019 and was distributed through TrickBot infections. Experts speculate the operators are members of a Russia-based cybercrime group known as Wizard Spider.
Since August 2020, the group has launched its leak site to threaten its victim to release the stolen data. Conti operators claimed to have already compromised at least 500 organisations worldwide.
Recently the Conti gang hit the attack on the Australian energy CS Energy and threaten to leak the stolen files.
After the disclosure of the exploit, Microsoft researchers reported that Nation-state actors from China, Iran, North Korea, and Turkey are now abusing the Log4Shell (CVE-2021-44228) in the Log4J library in their campaigns. Some of the groups exploiting the vulnerability are China-linked Hafnium and Iran-linked Phosphorus, the former group is using the flaw to attack virtualization infrastructure, the latter to deploy ransomware.
The IT giant also confirmed that the exploitation of the Log4Shell to deploy the Khonsari ransomware, as discussed by Bitdefender recently.
Microsoft experts also state that multiple access brokers have begun using the Log4Shell vulnerability to gain initial access to target networks and then sell it to ransomware-as-a-service affiliates.
Researchers from threat intelligence firm AdvIntel, the Conti ransomware gang started attempting to exploit the Log4Shell issue the day after the disclosure of the exploit.
“And indeed, a week after the Log4j2 vulnerability became public, AdvIntel discovered the most concerning trend – the exploitation of the new CVE by one of the most prolific organized ransomware groups – Conti.” reads the analysis published by AdvIntel.
The gang and its affiliates started targeting VMware vCenter servers because the virtualization giant has yet to release a fix for the flaw.
“A malicious actor with network access to an impacted VMware product may exploit this issue to gain full control of the target system and/or perform a denial of service attack” reads the advisory published by VMware.
Below is the ransomware exploitation timeline published by AdvIntel:
On December 12, AdvIntel discovered that multiple Conti group members that were attempting to exploit the vulnerability for the initial attack vector.
“The current exploitation led to multiple use cases through which the Conti group tested the possibilities of utilizing the Log4J2 exploit. Most importantly, AdvIntel confirmed that the criminals pursued targeting specific vulnerable Log4J2 VMware vCenter for lateral movement directly from the compromised network resulting in vCenter access affecting US and European victim networks from the pre-existent Cobalt Strike sessions.” continues AdvIntel.
Experts believe that it is only a matter of time until Conti and other threat actors will exploit the Log4j to its full capacity.
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