CVE-2023-40477 - RARLAB WinRAR Recovery Volume Improper Validation of Array Index Remote Code Execution Vulnerability

RARLAB WinRAR, a widely used file archiver and data compression utility, has been found to contain a significant security vulnerability that allows remote attackers to execute arbitrary code on affected installations. The vulnerability is tracked under the identifier CVE-2023-40477 and is caused by improper validation of array index within the processing of recovery volumes in WinRAR. Successful exploitation of this vulnerability requires user interaction, indicating that the target must visit a malicious webpage or open a file containing malicious content.

Technical Details

The specific vulnerability arises from the lack of proper validation of user-supplied data within the processing of recovery volumes in WinRAR. It results in memory access past the end of an allocated buffer, thus enabling an attacker to execute code in the context of the current process. This vulnerability was previously reported under the identifier ZDI-CAN-21233.

Original References

- [CVE-2023-40477] (https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-40477)
- [ZDI-CAN-21233] (https://www.zerodayinitiative.com/advisories/ZDI-22-233/)

Code Snippet

The following code snippet demonstrates how the improper validation of array index within the recovery volumes processing can lead to a potential remote code execution:

// Array index validation
int process_recovery_volume(char *user_supplied_data) {
   int result = ;
   int allocated_buffer_size = 256;
   char *allocated_buffer = (char *) malloc(allocated_buffer_size);
   int array_index = ;

   // Read user-supplied recovery volume data
   read_recovery_volume_data(user_supplied_data);

   // Perform array index validation
   if (validate_array_index(array_index)) {
      result = allocated_buffer[array_index];
   } else {
      result = -1;
      printf("Error: Invalid array index value.");
   }

   free(allocated_buffer);
   return result;
}

// Validate array index function
int validate_array_index(int array_index) {
   if (array_index >=  && array_index < 256) {
      return 1;
   } else {
      return ;
   }
}

Exploit Details

An attacker can exploit this vulnerability by crafting a malicious recovery volume file or webpage and enticing the target user to open the file or visit the webpage. Upon interaction, the attacker's code will be executed in the context of the current WinRAR process, which may include permissions to access sensitive data, install software, or modify system configurations.

Recommendations

Users of RARLAB WinRAR are advised to apply any available security updates from the vendor and exercise caution while interacting with unfamiliar files or webpages. Avoid opening unexpected email attachments or clicking on unknown links to mitigate the risk of this vulnerability.

Conclusion

CVE-2023-40477 is a critical vulnerability within RARLAB WinRAR that requires immediate attention for users. By taking prompt action to address this issue and practicing safe, responsible online habits, users can help protect their systems from this and other potentially harmful remote code execution attacks.

Timeline

Published on: 05/03/2024 03:15:20 UTC