SSH Server | Breaking Cybersecurity News | The Hacker News

Security researchers from Ruhr University Bochum have discovered a vulnerability in the Secure Shell ( SSH ) cryptographic network protocol that could allow an attacker to downgrade the connection's security by breaking the integrity of the secure channel. Called  Terrapin  ( CVE-2023-48795 , CVSS score: 5.9), the exploit has been described as the "first ever practically exploitable prefix truncation attack." "By carefully adjusting the sequence numbers during the handshake, an attacker can remove an arbitrary amount of messages sent by the client or server at the beginning of the secure channel without the client or server noticing it," researchers Fabian Bäumer, Marcus Brinkmann, and Jörg Schwenk  said . SSH is a  method  for securely sending commands to a computer over an unsecured network. It relies on cryptography to authenticate and encrypt connections between devices. This is accomplished by means of a handshake in which a client and server agree up

Poorly secured Linux SSH servers are being targeted by bad actors to install port scanners and dictionary attack tools with the goal of targeting other vulnerable servers and co-opting them into a network to carry out cryptocurrency mining and distributed denial-of-service (DDoS) attacks. "Threat actors can also choose to install only scanners and sell the breached IP and account credentials on the dark web," the AhnLab Security Emergency Response Center (ASEC)  said  in a report on Tuesday. In these attacks, adversaries try to guess a server's SSH credentials by running through a list of commonly used combinations of usernames and passwords, a technique called dictionary attack. Should the brute-force attempt be successful, it's followed by the threat actor deploying other malware, including scanners, to scan for other susceptible systems on the internet. Specifically, the scanner is designed to look for systems where port 22 -- which is associated with the SSH

As a relatively new security category, many security operators and executives I've met have asked us "What are these Automated Security Validation (ASV) tools?" We've covered that pretty extensively in the past, so today, instead of covering the " What is ASV?" I wanted to address the " Why ASV?" question. In this article, we'll cover some common use cases and misconceptions of how people misuse and misunderstand ASV tools daily (because that's a lot more fun). To kick things off, there's no place to start like the beginning. Automated security validation tools are designed to provide continuous, real-time assessment of an organization's cybersecurity defenses. These tools are continuous and use exploitation to validate defenses like EDR, NDR, and WAFs. They're more in-depth than vulnerability scanners because they use tactics and techniques that you'll see in manual penetration tests. Vulnerability scanners won't relay hashes or combine vulnerabilities to further attacks, whic