Researchers have demonstrated a method for cracking the Akira ransomware's encryption using sixteen RTX 4090 GPUs. By exploiting a vulnerability in Akira's implementation of the ChaCha20 encryption algorithm, they were able to brute-force the 256-bit encryption key in approximately ten hours. This breakthrough signifies a potential weakness in the ransomware and offers a possible recovery route for victims, though the required hardware is expensive and not readily accessible to most. The attack relies on Akira's flawed use of a 16-byte (128-bit) nonce, effectively reducing the key space and making it susceptible to this brute-force approach.
The post "Learn How to Break AES" details a hands-on educational tool for exploring vulnerabilities in simplified versions of the AES block cipher. It provides a series of interactive challenges where users can experiment with various attack techniques, like differential and linear cryptanalysis, against weakened AES implementations. By manipulating parameters like the number of rounds and key size, users can observe how these changes affect the cipher's security and practice applying cryptanalytic methods to recover the encryption key. The tool aims to demystify advanced cryptanalysis concepts by providing a visual and interactive learning experience, allowing users to understand the underlying principles of these attacks and the importance of a full-strength AES implementation.
HN commenters discuss the practicality and limitations of the "block breaker" attack described in the article. Some express skepticism, pointing out that the attack requires specific circumstances and doesn't represent a practical break of AES. Others highlight the importance of proper key derivation and randomness, reinforcing that the attack exploits weaknesses in implementation rather than the AES algorithm itself. Several comments delve into the technical details, discussing the difference between a chosen-plaintext attack and a known-plaintext attack, as well as the specific conditions under which the attack could be successful. The overall consensus seems to be that while interesting, the "block breaker" is not a significant threat to AES security when implemented correctly. Some appreciate the visualization and explanation provided by the article, finding it helpful for understanding block cipher vulnerabilities in general.
A hacker tricked approximately 18,000 aspiring cybercriminals ("script kiddies") by distributing a fake malware builder. Instead of creating malware, the tool actually infected their own machines with a clipper, which silently replaces cryptocurrency wallet addresses copied to the clipboard with the attacker's own, diverting any cryptocurrency transactions to the hacker. This effectively turned the tables on the would-be hackers, highlighting the risks of using untrusted tools from underground forums.
HN commenters largely applaud the vigilante hacker's actions, viewing it as a form of community service by removing malicious actors and their potential harm. Some express skepticism about the 18,000 figure, suggesting it's inflated or that many downloads may not represent active users. A few raise ethical concerns, questioning the legality and potential collateral damage of such actions, even against malicious individuals. The discussion also delves into the technical aspects of the fake builder, including its payload and distribution method, with some speculating on the hacker's motivations beyond simple disruption.
DoubleClickjacking is a clickjacking technique that tricks users into performing unintended actions by overlaying an invisible iframe containing an ad over a legitimate clickable element. When the user clicks what they believe to be the legitimate element, they actually click the hidden ad, generating revenue for the attacker or redirecting the user to a malicious site. This exploit leverages the fact that some ad networks register clicks even if the ad itself isn't visible. DoubleClickjacking is particularly concerning because it bypasses traditional clickjacking defenses that rely on detecting visible overlays. By remaining invisible, the malicious iframe effectively hides from security measures, making this attack difficult to detect and prevent.
Hacker News users discussed the plausibility and impact of the "DoubleClickjacking" technique described in the linked article. Several commenters expressed skepticism, arguing that the described attack is simply a variation of existing clickjacking techniques, not a fundamentally new vulnerability. They pointed out that modern browsers and frameworks already have mitigations in place to prevent such attacks, like the X-Frame-Options header. The discussion also touched upon the responsibility of ad networks in preventing malicious ads and the effectiveness of user education in mitigating these types of threats. Some users questioned the practicality of the attack, citing the difficulty in precisely aligning elements for the exploit to work. Overall, the consensus seemed to be that while the described scenario is technically possible, it's not a novel attack vector and is already addressed by existing security measures.
Summary of Comments ( 11 )
https://news.ycombinator.com/item?id=43387188
Hacker News commenters discuss the practicality and implications of using RTX 4090 GPUs to crack Akira ransomware. Some express skepticism about the real-world applicability, pointing out that the specific vulnerability exploited in the article is likely already patched and that criminals will adapt. Others highlight the increasing importance of strong, long passwords given the demonstrated power of brute-force attacks with readily available hardware. The cost-benefit analysis of such attacks is debated, with some suggesting the expense of the hardware may be prohibitive for many victims, while others counter that high-value targets could justify the cost. A few commenters also note the ethical considerations of making such cracking tools publicly available. Finally, some discuss the broader implications for password security and the need for stronger encryption methods in the future.
The Hacker News post titled "Akira ransomware can be cracked with sixteen RTX 4090 GPUs in around ten hours" has generated several comments discussing the implications of using powerful GPUs like the RTX 4090 for cracking encryption.
Some users express skepticism about the practicality of this approach. One commenter questions the feasibility for average users, pointing out the significant cost of acquiring sixteen RTX 4090 GPUs. They suggest that while technically possible, the financial barrier makes it unlikely for most victims of ransomware. Another user echoes this sentiment, highlighting that the cost would likely exceed the ransom demand in many cases. They also raise the point that this method might only work for a specific vulnerability in Akira and wouldn't be a universal solution for all ransomware.
Others discuss the broader implications of readily available GPU power. One comment points out the increasing accessibility of powerful hardware and its potential to empower both security researchers and malicious actors. They argue that this development underscores the ongoing "arms race" in cybersecurity, where advancements in technology benefit both sides. Another user suggests that this highlights the importance of robust encryption practices, as the increasing power of GPUs could eventually render weaker encryption methods vulnerable.
A few comments delve into the technical aspects. One user questions the specific algorithm used by Akira and speculates on its susceptibility to brute-force attacks. Another user mentions the importance of key length and how it affects the time required for cracking, emphasizing that longer keys would significantly increase the difficulty even with powerful GPUs.
One commenter points out the article's potentially misleading title. They clarify that the GPUs weren't cracking the encryption itself, but rather brute-forcing a password which was then used to decrypt the files. This distinction is important, as it implies a weakness in the implementation rather than the underlying encryption algorithm.
Finally, a few users offer practical advice. One suggests using strong, unique passwords to protect against this type of attack, emphasizing the importance of basic security hygiene. Another user proposes that the best defense against ransomware remains regular backups, allowing victims to restore their data without paying the ransom.
Overall, the comments reflect a mix of concerns about the practical implications of using GPUs for cracking ransomware, discussions about the broader cybersecurity landscape, and technical insights into the vulnerabilities highlighted by this specific case.