Windows Zero-Day (CVE-2023-28252)
CVE-2023-28252 is a security vulnerability that can allow an attacker to execute arbitrary code on a system running the affected software. To protect against this vulnerability and other similar ones, it is important to keep software up to date and use additional security measures where possible.
Yesterday, April 11th 2023, Microsoft patched an actively exploited Zero-Day vulnerability known as CVE-2023-28252, along with 96 other vulnerabilities.
What is CVE-2023-28252? (Simplified)
CVE-2023-28252 is a security vulnerability in Microsoft Windows that allows an attacker to access sensitive information or take control of a system.
CVE-2023-28252 is a buffer overflow that affects the Windows Common Log File System (CLFS). When the CLFS service is running and is storing data in a specific locations in its memory. If an attacker sends too much data to this location, it can overflow the buffer and cause CLFS to crash or behave unpredictably.
In the case of CVE-2023-28252, an attacker can use this vulnerability to run arbitrary code on the affected system. This means that they can execute any command or program they wish, giving them complete control over the system.
This could allow an attacker to steal sensitive data, install malware or ransomware, or even use the compromised system to carry out further attacks on other systems.
To mitigate CVE-2023-28252 and other similar vulnerabilities, it is important to keep all software up to date with the latest security patches and updates. Software vendors often release these updates specifically to address security vulnerabilities that have been discovered. It is also a good idea to use antivirus and other security software to provide an additional layer of protection against attacks.
What is CVE-2023-28252? (Detailed)
CVE-2023-28252 is a security vulnerability that affects the Windows Common Log File System (CLFS). This vulnerability allows an attacker to execute arbitrary code on a system running the affected software.
The Windows Common Log File System
The Windows Common Log File System (CLFS) is a log file management system that is used by applications in the Windows operating system. CLFS provides a centralized platform to manage logs that are written by various applications and services. CLFS is used by many applications, including database systems, file systems, and various Windows services.
The Vulnerability
CVE-2023-28252 is a buffer overflow vulnerability that exists in CLFS. A buffer overflow vulnerability occurs when a program tries to write more data to a memory location than it can hold, causing the excess data to overwrite adjacent memory locations and can result in unexpected behaviour, including system crashes, data corruption, and even execution of arbitrary code.
The vulnerability in CLFS exists in the way that it handles log records. When a log record is written to the CLFS, it is first cached in memory. The vulnerability occurs when the CLFS attempts to flush this cached log record to disk. If the size of the log record is greater than the size of the cache buffer, a buffer overflow can occur, allowing an attacker to execute arbitrary code.
Exploitation
To exploit this vulnerability, an attacker needs to send a specially crafted log record to the CLFS. The log record must be large enough to cause a buffer overflow when the CLFS tries to flush it to disk. By doing so, an attacker can overwrite adjacent memory locations and execute arbitrary code.
The exploitation of this vulnerability requires local access to the system. Therefore, an attacker needs to have access to the host to exploit this issue. However, once an attacker has exploited the vulnerability, they can gain complete SYSTEM control.
Mitigation
Microsoft has released a security patch to address this vulnerability. The patch fixes the vulnerability by ensuring that the CLFS component correctly handles log records that are larger than the cache buffer. As a best practice, it is recommended to always keep your software up to date with the latest security patches and updates. Additionally, organizations should monitor their systems for any signs of exploitation, including unexpected system crashes, data corruption, and unauthorized system access.
Public Exploit Code
As of April 12th 2023, no exploit code in the public domain exists to take advantage of this flaw. However, the vulnerability is being actively exploited by ransomware operators and thus, working code does exist and will likely be made public in the near future.
