According to SonarSource, an open-source alternative to email servers and collaboration platforms such as Microsoft Exchange. Since May 10, 2022, a patch has been released in Zimbra versions ZCS 9.0.0 Patch 24.1 and ZCS 8.8.15 Patch 31.1. Zimbra is utilized by organizations, governments, and financial institutions throughout the world.
Unauthenticated attackers might contaminate an unwary victim's cache, according to Simon Scannell, a vulnerability researcher at Swiss security firm Sonar. The vulnerability has been assigned the number CVE-2022-27924 (CVSS: 7.5), and it has been described as a case of "Memcached poisoning with unauthorized access," which might allow an attacker to inject malicious commands and steal sensitive data.
Since newline characters (\r\n) in untrusted user input were not escaped, attackers were able to inject arbitrary Memcached instructions into a targeted instance, causing cached entries to be overwritten. Memcached servers keep track of key/value pairs that may be created and retrieved using a simple text-based protocol and analyze data line by line. A malicious actor might alter the IMAP route entries for a known username by sending a specially crafted HTTP request to the susceptible Zimbra server, according to the researchers. When the genuine user logs in, the Nginx Proxy in Zimbra will send all IMAP communication, including the credentials in plain text, to the attacker.
Knowing the victim's email address, and utilizing an IMAP client makes it easier for the attacker to abuse the vulnerability. A second attack technique allows users to circumvent the aforesaid constraints and steal credentials for any user with no involvement or knowledge of the Zimbra instance. This is accomplished through "Response Smuggling," a different approach that makes use of a web-based Zimbra client. Cross-site scripting (XSS) and SQL injection issues caused by a lack of input escaping "are well known and documented for decades," as per Scannell, but "other injection vulnerabilities can occur that are less well known and can have a catastrophic consequence."
As a result Scannell, advises programmers to "be cautious of special characters that should be escaped when coping with technology where there is less documentation and research regarding potential vulnerabilities." The bug was discovered four months after Zimbra provided a hotfix for an XSS flaw that was exploited in a series of sophisticated spear-phishing efforts attributed to an undisclosed Chinese threat group.
