CVE-2018-1000888: Surprise, another remote code execution vulnerability

In this post we take a closer look at CVE-2018-1000888. Below you can take a look if any exploits are available and if they have been published in the exploit database.

Common Vulnerabilities and Exposures is a rundown of sections-each containing a recognizable proof number, a portrayal, and no less than one open reference-for freely known cybersecurity vulnerabilities. CVE Entries are utilized in various cybersecurity items and administrations from around the globe.

About CVE-2018-1000888

PEAR Archive_Tar version 1.4.3 and earlier contains a CWE-502, CWE-915 vulnerability in the Archive_Tar class. There are several file operations with `$v_header[‘filename’]` as parameter (such as file_exists, is_file, is_dir, etc). When extract is called without a specific prefix path, we can trigger unserialization by crafting a tar file with `phar://[path_to_malicious_phar_file]` as path. Object injection can be used to trigger destruct in the loaded PHP classes, e.g. the Archive_Tar class itself. With Archive_Tar object injection, arbitrary file deletion can occur because `@unlink($this->_temp_tarname)` is called. If another class with useful gadget is loaded, it may possible to cause remote code execution that can result in files being deleted or possibly modified. This vulnerability appears to have been fixed in 1.4.4.

Additional References

  • https://pear.php.net/bugs/bug.php?id=23782
  • https://blog.ripstech.com/2018/new-php-exploitation-technique/
  • https://cdn2.hubspot.net/hubfs/3853213/us-18-Thomas-It%27s-A-PHP-Unserialization-Vulnerability-Jim-But-Not-As-We-….pdf
  • https://pear.php.net/package/Archive_Tar/download/