An open source Log4j logging software has a major zero-day vulnerability that affects a who’s who of the Internet’s most well-known service providers, such as Apple, Amazon, Cloudflare, Steam and Tesla’s Tesla Model S.
On Thursday afternoon, multiple Minecraft services and news sites issued a warning about a current attack code that used the Log4Shell vulnerability to execute malicious code on Minecraft servers and clients. Before long it was evident that Minecraft was only one of several well-known websites at risk of similar assaults.
Some of the most widely used and trusted cloud-based services throughout the world may be seen in action in a series of screenshots that have been released online. To put it another way:
If the target cloud service is executing a DNS search, the images use dnslog.cn, a domain name leak detection service. An attacker-controlled computer can be seen making connections to the service in each picture (as evidenced by the IP connection log).
A reader of Ars commented below, “Normally, putting something into a username box should never be establishing any external network connections. This demonstrates that Log4j is being utilised here and consequently the server may be exposed to the remote code execution attack.
Despite the fact that the photos demonstrate the services responding to user input in unexpected and potentially harmful ways, the services are not inevitably vulnerable to the sorts of code-execution assaults that compromised Minecraft servers. Why? Because they’re designed with numerous defences. For example, if a single layer fails, other layers may be available to reduce or eliminate any significant harm.
However, the photographs show that unauthorised individuals may use Log4Shell to get illegal access to the servers of some of the world’s largest organisations. Asked about Apple servers, Malwarebytes Mac head Thomas Reed said: “This is significantly worse than if individual devices were exposed, and I believe it’s an open issue at this moment just what type of data attackers are probably extracting from Apple’s services at this time.” If you tried to reach out to Apple for comment, no one got back to you.
According to a blog post by Cloudflare, the company has taken measures to prevent attacks on its network and those of its clients. There is no way for Cloudflare Chief Security Officer Joe Sullivan to replicate the behaviour represented in this image and he does not recognise the IP addresses indicated.
A patch for Minecraft was released on Friday.
The lesson here is that it’s too early to rule out the possibility that these services may be compromised. Individuals should stay cautious and wait for instructions from the impacted service providers.