CVE-2023-28262: Unmasking the Visual Studio Elevation of Privilege Vulnerability

A newly discovered security vulnerability, dubbed CVE-2023-28262, has been found to affect Microsoft Visual Studio's installer engine. This vulnerability could allow an attacker to elevate their privileges on a victim's system. In this blog post, we will walk you through the details of this vulnerability, providing code snippets, linking to original references, and exploring the potential exploit techniques.

What is CVE-2023-28262?

CVE-2023-28262 is a security vulnerability affecting the Microsoft Visual Studio installer engine. It is an elevation of privilege (EoP) vulnerability, meaning that it allows an attacker to gain higher-level permissions on a targeted system than they initially possess. This can be particularly dangerous, as the attacker can leverage these elevated privileges to perform actions typically reserved for higher-level users or even system administrators.

Vulnerability Details

The vulnerability exists due to improper handling of file paths and symbolic links (symlinks) in the Visual Studio installer. Symbolic links are special files that point to another file or directory on a computer system. Essentially, they act as shortcuts, allowing users and applications to access specific resources without knowing their exact locations.

The flaw in the installer engine can be exploited to overwrite arbitrary files on the victim's system by tricking the engine into following a malicious symbolic link. By overwriting system files, an attacker can manipulate the system's behavior and potentially execute arbitrary code with elevated privileges.

Here is a simplified code snippet that demonstrates the flaw in the installer

// Install function from the vulnerable installer
void install(char *src, char *dst) {
  // Resolve symbolic links for the destination file
  // (This is where the vulnerability lies)
  char *resolved_dst = resolve_symlinks(dst);

  // Check if the resolved destination file exists
  if (file_exists(resolved_dst)) {
    // If the file exists, overwrite it with the source file
    copy_file(src, resolved_dst);
  } else {
    // If the file doesn't exist, create it and perform the copy
    create_file(resolved_dst);
    copy_file(src, resolved_dst);
  }
}

Notice that the install function resolves the symbolic links before checking whether the destination file exists. An attacker can exploit this behavior by creating a malicious symlink that points to a protected system file and then triggering the installer function.

Links to Original References

1. CVE-2023-28262 entry on the NIST National Vulnerability Database (NVD): https://nvd.nist.gov/vuln/detail/CVE-2023-28262
2. Microsoft's Security Advisory detailing the vulnerability: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-28262

Exploitation Details

To exploit this vulnerability, an attacker would first need to gain access to the vulnerable system. This can be accomplished through various means, including exploiting another vulnerability, socially engineering the victim, or leveraging an existing foothold (e.g., malware).

Once the attacker has access to the system, they can create a malicious symbolic link and cause the Visual Studio installer (or a vulnerable component) to overwrite a system file with attacker-controlled data. This can lead to an elevation of privilege, allowing the attacker to perform actions otherwise reserved for higher-level users or system administrators.

Mitigation and Recommendations

Microsoft has released a security update to address the CVE-2023-28262 vulnerability. Users and administrators are strongly encouraged to apply the update as soon as possible to mitigate the risk associated with this vulnerability. The update can be obtained through the Microsoft Update Catalog or Visual Studio's built-in update mechanism.

Additionally, users should exercise caution when installing software, as compromised installer packages could potentially be used to exploit this vulnerability. It is always a good idea to verify the source of the software you are installing and ensure that it is from a trusted party. Utilize the practice of least privilege by running software and services using the minimal permissions necessary.

Conclusion

CVE-2023-28262 is a dangerous elevation of privilege vulnerability affecting the Visual Studio installer engine. By exploiting this flaw, an attacker can gain higher-level permissions on a targeted system and cause significant damage. To protect yourself and your organization, it is critical to apply the security update provided by Microsoft and follow best practices for securing your systems.

Timeline

Published on: 04/11/2023 21:15:00 UTC
Last modified on: 04/18/2023 20:51:00 UTC