The Times Australia
The Times World News

.
The Times Real Estate

.

What is Log4j? A cybersecurity expert explains the latest internet vulnerability, how bad it is and what's at stake

  • Written by Santiago Torres-Arias, Assistant Professor of Electrical and Computer Engineering, Purdue University
What is Log4j? A cybersecurity expert explains the latest internet vulnerability, how bad it is and what's at stake

Log4Shell, an internet vulnerability that affects millions of computers, involves an obscure but nearly ubiquitous piece of software, Log4j. The software is used to record all manner of activities that go on under the hood in a wide range of computer systems.

Jen Easterly, director of the U.S. Cybersecurity & Infrastructure Security Agency, called Log4Shell the most serious vulnerability[1] she’s seen in her career. There have already been hundreds of thousands, perhaps millions, of attempts to exploit the vulnerability[2].

So what is this humble piece of internet infrastructure, how can hackers exploit it and what kind of mayhem could ensue?

a woman with long dark hair wearing eyeglasses speaks into a microphone
Cybersecurity & Infrastructure Security Agency director Jen Easterly called Log4Shell ‘the most serious vulnerability I’ve seen.’ Kevin Dietsch/Getty Images News[3]

What does Log4j do?

Log4j records events – errors and routine system operations – and communicates diagnostic messages about them to system administrators and users. It’s open-source software[4] provided by the Apache Software Foundation[5].

A common example of Log4j at work is when you type in or click on a bad web link and get a 404 error message. The web server running the domain of the web link you tried to get to tells you that there’s no such webpage. It also records that event in a log for the server’s system administrators using Log4j.

Similar diagnostic messages are used throughout software applications. For example, in the online game Minecraft, Log4j is used by the server to log activity like total memory used and user commands typed into the console.

How does Log4Shell work?

Log4Shell works by abusing a feature in Log4j that allows users to specify custom code for formatting a log message. This feature allows Log4j to, for example, log not only the username associated with each attempt to log in to the server but also the person’s real name, if a separate server holds a directory linking user names and real names. To do so, the Log4j server has to communicate with the server holding the real names.

Unfortunately, this kind of code can be used for more than just formatting log messages. Log4j allows third-party servers to submit software code that can perform all kinds of actions on the targeted computer. This opens the door for nefarious activities such as stealing sensitive information, taking control of the targeted system and slipping malicious content to other users communicating with the affected server.

It is relatively simple to exploit Log4Shell. I was able to reproduce the problem in my copy of Ghidra[6], a reverse-engineering framework for security researchers, in just a couple of minutes. There is a very low bar for using this exploit, which means a wider range of people with malicious intent can use it.

Log4j is everywhere

One of the major concerns about Log4Shell is Log4j’s position in the software ecosystem. Logging is a fundamental feature of most software, which makes Log4j very widespread[7]. In addition to popular games like Minecraft, it’s used in cloud services like Apple iCloud and Amazon Web Services, as well as a wide range of programs from software development tools[8] to security tools[9].

Open-source software like Log4j is used in so many products and tools that some organizations don’t even know which pieces of code are on their computers.

This means hackers have a large menu of targets to choose from: home users, service providers, source code developers and even security researchers. So while big companies like Amazon can quickly patch their web services to prevent hackers from exploiting them, there are many more organizations that will take longer to patch their systems, and some that might not even know they need to.

The damage that can be done

Hackers are scanning through the internet to find vulnerable servers and setting up machines that can deliver malicious payloads. To carry out an attack, they query services (for example, web servers) and try to trigger a log message (for example, a 404 error). The query includes maliciously crafted text, which Log4j processes as instructions.

These instructions can create a reverse shell[10], which allows the attacking server to remotely control the targeted server, or they can make the target server part of a botnet[11]. Botnets use multiple hijacked computers to carry out coordinated actions on behalf of the hackers.

A large number of hackers[12] are already trying to abuse Log4Shell. These range from ransomware gangs locking down minecraft servers[13] to hacker groups trying to mine bitcoin[14] and hackers associated with China and North Korea[15] trying to gain access to sensitive information from their geopolitical rivals. The Belgian ministry of defense reported that its computers were being attacked using Log4Shell[16].

Although the vulnerability first came to widespread attention on Dec. 10, 2021, people are still identifying new ways[17] to cause harm through this mechanism.

Stopping the bleeding

It is hard to know whether Log4j is being used in any given software system because it is often bundled as part of other software[18]. This requires system administrators to inventory their software to identify its presence. If some people don’t even know they have a problem, it’s that much harder to eradicate the vulnerability.

Another consequence of Log4j’s diverse uses is there is no one-size-fits-all solution to patching it. Depending on how Log4j was incorporated in a given system, the fix will require different approaches. It could require a wholesale system update, as done for some Cisco routers[19], or updating to a new version of software, as done in Minecraft[20], or removing the vulnerable code manually for those who can’t update the software.

Log4Shell is part of the software supply chain. Like physical objects people purchase, software travels through different organizations and software packages before it ends up in a final product. When something goes wrong, rather than going through a recall process, software is generally “patched[21],” meaning fixed in place.

However, given that Log4j is present in various ways in software products[22], propagating a fix requires coordination from Log4j developers, developers of software that use Log4j, software distributors, system operators and users. Usually, this introduces a delay between the fix being available in Log4j code and people’s computers actually closing the door on the vulnerability.

[Over 140,000 readers rely on The Conversation’s newsletters to understand the world. Sign up today[23].]

Some estimates for time-to-repair in software generally range from weeks to months[24]. However, if past behavior is indicative of future performance, it is likely the Log4j vulnerability will crop up for years to come[25].

As a user, you are probably wondering what can you do about all this. Unfortunately, it is hard to know whether a software product you are using includes Log4j and whether it is using vulnerable versions of the software. However, you can help by heeding the common refrain from computer security experts: Make sure all of your software is up to date.

References

  1. ^ most serious vulnerability (www.cnbc.com)
  2. ^ attempts to exploit the vulnerability (www.zdnet.com)
  3. ^ Kevin Dietsch/Getty Images News (www.gettyimages.com)
  4. ^ open-source software (www.businessinsider.com)
  5. ^ Apache Software Foundation (apache.org)
  6. ^ Ghidra (github.com)
  7. ^ Log4j very widespread (security.googleblog.com)
  8. ^ software development tools (wiki.eclipse.org)
  9. ^ security tools (github.com)
  10. ^ reverse shell (www.acunetix.com)
  11. ^ botnet (www.howtogeek.com)
  12. ^ large number of hackers (www.akamai.com)
  13. ^ ransomware gangs locking down minecraft servers (www.crn.com)
  14. ^ hacker groups trying to mine bitcoin (www.silentpush.com)
  15. ^ China and North Korea (www.microsoft.com)
  16. ^ attacked using Log4Shell (www.wsj.com)
  17. ^ new ways (www.theregister.com)
  18. ^ bundled as part of other software (deps.dev)
  19. ^ some Cisco routers (tools.cisco.com)
  20. ^ Minecraft (www.minecraft.net)
  21. ^ patched (www.techopedia.com)
  22. ^ present in various ways in software products (unit42.paloaltonetworks.com)
  23. ^ Sign up today (memberservices.theconversation.com)
  24. ^ weeks to months (www.rapid7.com)
  25. ^ will crop up for years to come (blog.malwarebytes.com)

Read more https://theconversation.com/what-is-log4j-a-cybersecurity-expert-explains-the-latest-internet-vulnerability-how-bad-it-is-and-whats-at-stake-173896

The Times Features

Best Deals on Home Furniture Online

Key Highlights Discover the best deals on high-quality outdoor furniture online. Transform your outdoor space into a stylish and comfortable oasis. Explore a wide range of d...

Discover the Best Women's Jumpers for Every Season

Key Highlights Explore lightweight jumpers for spring and summer, ensuring breathability and ease. Wrap up warm with cozy wool jumpers for the chilly autumn and winter season...

Uncover the Elegance of Gorgeous Diamond Tennis Necklaces

Key Highlights Diamond tennis necklaces are a timeless piece of jewelry that exudes elegance and sophistication. They feature a continuous line of brilliant-cut diamonds, cre...

Dental Implants vs. Dentures: Which Is Better for You?

When it comes to replacing missing teeth, two of the most common options are dental implants and dentures. Both have their advantages and disadvantages, so choosing between them ...

What Neck Pain Really Means (And Why It’s More Than Just Poor Posture)

Neck pain is often brushed off as something temporary — a tight spot after a long day at the desk or a poor night’s sleep. But when the discomfort keeps returning, it could be a ...

The Work of Gosha Rubchinskiy: Fashion, Culture, and Youth

From Designer to Cultural Architect Gosha Rubchinskiy is not just a fashion designer—he's a cultural force. Born in Moscow in 1984, Rubchinskiy began his career in fashion in t...

Times Magazine

The Essential Guide to Transforming Office Spaces for Maximum Efficiency

Why Office Fitouts MatterA well-designed office can make all the difference in productivity, employee satisfaction, and client impressions. Businesses of all sizes are investing in updated office spaces to create environments that foster collaborat...

The A/B Testing Revolution: How AI Optimized Landing Pages Without Human Input

A/B testing was always integral to the web-based marketing world. Was there a button that converted better? Marketing could pit one against the other and see which option worked better. This was always through human observation, and over time, as d...

Using Countdown Timers in Email: Do They Really Increase Conversions?

In a world that's always on, where marketers are attempting to entice a subscriber and get them to convert on the same screen with one email, the power of urgency is sometimes the essential element needed. One of the most popular ways to create urg...

Types of Software Consultants

In today's technology-driven world, businesses often seek the expertise of software consultants to navigate complex software needs. There are several types of software consultants, including solution architects, project managers, and user experienc...

CWU Assistive Tech Hub is Changing Lives: Win a Free Rollator Walker This Easter!

🌟 Mobility. Independence. Community. All in One. This Easter, the CWU Assistive Tech Hub is pleased to support the Banyule community by giving away a rollator walker. The giveaway will take place during the Macleod Village Easter Egg Hunt & Ma...

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

LayBy Shopping