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The Hacker News - Cybersecurity News and Analysis: ssh security

36-Year-Old SCP Clients' Implementation Flaws Discovered

36-Year-Old SCP Clients' Implementation Flaws Discovered

January 15, 2019Mohit Kumar
A set of 36-year-old vulnerabilities has been uncovered in the Secure Copy Protocol (SCP) implementation of many client applications that can be exploited by malicious servers to overwrite arbitrary files in the SCP client target directory unauthorizedly. Session Control Protocol (SCP), also known as secure copy, is a network protocol that allows users to securely transfer files between a local host and a remote host using RCP (Remote Copy Protocol) and SSH protocol. In other terms, SCP, which dates back to 1983, is a secure version of RCP that uses authentication and encryption of SSH protocol to transfer files between a server and a client. Discovered by Harry Sintonen, one of F-Secure's Senior Security Consultants, the vulnerabilities exist due to poor validations performed by the SCP clients, which can be abused by malicious servers or man-in-the-middle (MiTM) attackers to drop or overwrite arbitrary files on the client's system. "Many scp clients fail to ver
LibSSH Flaw Allows Hackers to Take Over Servers Without Password

LibSSH Flaw Allows Hackers to Take Over Servers Without Password

October 17, 2018Mohit Kumar
A four-year-old severe vulnerability has been discovered in the Secure Shell (SSH) implementation library known as Libssh that could allow anyone to completely bypass authentication and gain unfettered administrative control over a vulnerable server without requiring a password. The security vulnerability, tracked as CVE-2018-10933 , is an authentication-bypass issue that was introduced in Libssh version 0.6 released earlier 2014, leaving thousands of enterprise servers open to hackers for the last four years. But before you get frightened, you should know that neither the widely used OpenSSH nor Github's implementation of libssh was affected by the vulnerability. The vulnerability resides due to a coding error in Libssh and is "ridiculously simple" to exploit. According to a security advisory published Tuesday, all an attacker needs to do is sending an "SSH2_MSG_USERAUTH_SUCCESS" message to a server with an SSH connection enabled when it expects an &
Bug in OpenSSH Opens Linux Machines to Password Cracking Attack

Bug in OpenSSH Opens Linux Machines to Password Cracking Attack

July 23, 2015Swati Khandelwal
A simple but highly critical vulnerability recently disclosed in the most widely used OpenSSH software allows attackers to try thousands of password login attempts per connection in a short period. OpenSSH is the most popular software widely used for secure remote access to Linux-based systems. Generally, the software allows 3 to 6 Password login attempts before closing a connection, but a new vulnerability lets attackers perform thousands of authentication requests remotely . OpenSSH servers with keyboard-interactive authentication enabled , including FreeBSD Linux, can be exploited to carry out the brute force attack on OpenSSH protocol, a security researcher with online alias KingCope explained in a blog post . Exploit for the Vulnerability RELEASED  Hackers could widely exploit the vulnerability because the keyboard-interactive authentication is by default enabled on most of the systems. Researcher has also released a proof-of-concept exploit code, which i
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