CVE-2018-1000888 Archive_Tar contains Potential RCE if filename starts with phar://

What is CVE-2018-1000888?

CVE-2018-1000888 is a high-severity unsafe deserialization vulnerability in Canonical Ubuntu Linux, published on 27 Dec 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

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.

Weakness: CWE-502

Which versions are affected by CVE-2018-1000888?

2 open source packages ship an affected version, including pear/archive_tar. It affects 3 products.

Products include Canonical Ubuntu Linux, Debian Debian Linux, Php Pear Archive Tar.

How do I fix CVE-2018-1000888?

Upgrade pear/archive_tar to 1.4.4 or later.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2018-1000888 being exploited?

There is no known exploitation of CVE-2018-1000888 in the wild and no public exploit code.

Public exploit code: 1 Exploit-DB entry.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CLEANSTART-2024-AG03928, DEBIAN-CVE-2018-1000888, DLA-1674-1, DSA-4378-1, GHSA-3q76-jq6m-573p, UBUNTU-CVE-2018-1000888 and 1 more.