PHP addressed critical RCE potentially impacting millions of servers
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2012-1823 | PHP-CGI Query String Parsing Flaw Enables Unauthenticated Remote Code Execution PHP, when the interpreter is exposed through the CGI (php-cgi) interface, mishandles query strings (CWE-20 improper input validation), allowing attackers to pass command-line switches such as -d and -s directly to the interpreter. A remote, unauthenticated attacker triggers the flaw by sending a crafted query string beginning with a dash (including URL-encoded forms) to any URL handled by php-cgi. Successful exploitation allows arbitrary code execution under the web server's privileges, as well as disclosure of script source code or phpinfo output, with no authentication required. Only deployments that invoke PHP via CGI/FastCGI (common in legacy shared hosting and bundled software stacks) are affected; PHP running as an Apache module or via PHP-FPM is not exposed. The flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2022-03-25 with EPSS at 100%, indicating active in-the-wild exploitation; any ransomware association is not yet confirmed. Do: Upgrade PHP to at least 5.3.13/5.4.3 or, preferably, a currently supported PHP branch, and stop exposing the php-cgi binary directly by moving to mod_php or PHP-FPM. As an interim mitigation, block or rewrite requests whose query string begins with a dash (e.g., -d, -s, or URL-encoded dash characters) and review web server logs for such patterns to detect prior exploitation. | — | 100% | KEV |
| masshundreds of thousands of internet-exposed php-cgi endpoints (a subset of the tens of millions of PHP-powered websites) | |
| CVE-2024-4577 | OS Command Injection in Windows PHP-CGI Allows Remote Code Execution CVE-2024-4577 is an OS command injection flaw (CWE-78) in Windows-based PHP when it runs in CGI mode, allowing arbitrary code execution on the server. It is triggered when attacker-supplied characters in HTTP requests are mishandled by Windows' character-encoding conversion as the OS invokes php-cgi, letting attackers inject command-line arguments to the PHP interpreter; this bypasses the decade-old fix for CVE-2012-1823. A successful attacker gains the ability to run arbitrary commands and code in the context of the web server. Affected systems are PHP running on Windows through the CGI interface; deployments that do not use PHP-CGI on Windows are not described as affected in the source data. Exploitation is active: the flaw was added to CISA KEV on 2024-06-12 with known ransomware use, and EPSS assigns roughly 100% probability of exploitation within 30 days. Do: Per the CISA KEV required action, apply mitigations per vendor instructions or discontinue use: upgrade Windows PHP-CGI deployments to a PHP release that fixes CVE-2024-4577 per PHP Group advisories, or stop using CGI mode on Windows (e.g., switch to FastCGI) and apply any vendor-recommended workarounds. Given known ransomware abuse, review web server access logs for exploitation attempts (notably %AD-encoded soft hyphens and injected -d/-s arguments in php-cgi query strings) and prioritize patching internet-facing Windows hosts. | 9.8 | 100% | KEV ransomware PoC ×11 |
| large≈10,000–100,000 internet-exposed Windows PHP-CGI systems |
Full article574 words · extracted from securityaffairs.com · click to collapse
A new PHP for Windows remote code execution (RCE) flaw affects version 5.x and earlier versions, potentially impacting millions of servers worldwide.
Researchers at cybersecurity firm DEVCORE discovered a critical remote code execution (RCE) vulnerability, tracked as CVE-2024-4577, in the PHP programming language. An unauthenticated attacker can exploit the flaw to take full control of affected servers.
PHP is a popular open-source scripting language widely used for web development.
“While implementing PHP, the team did not notice the Best-Fit feature of encoding conversion within the Windows operating system. This oversight allows unauthenticated attackers to bypass the previous protection of CVE-2012-1823 by specific character sequences. Arbitrary code can be executed on remote PHP servers through the argument injection attack.” reads the advisory published by DEVCORE.
The vulnerability CVE-2024-4577 was reported to the PHP development team by the Devcore researcher Orange Tsai on May 7, 2024. The developers released a version that address the issue on June 6, 2024.
The flaw resides in the Best-Fit feature of encoding conversion within the Windows operating system. An attacker can exploit the flaw to bypass protections for a previous vulnerability, CVE-2012-1823, using specific character sequences. Consequently, arbitrary code can be executed on remote PHP servers through an argument injection attack, allowing attackers to take control of vulnerable servers.
Since the disclosure of the vulnerability and publicly availability of a PoC exploit code, multiple actors are attempting to exploit it, reported Shadowserver and GreyNoise researchers.
Shadowserver researchers observed multiple IPs testing PHP/PHP-CGI CVE-2024-4577 (Argument Injection Vulnerability) against its honeypot sensors starting on June 7th.
— The Shadowserver Foundation (@Shadowserver) June 7, 2024Attention! We see multiple IPs testing PHP/PHP-CGI CVE-2024-4577 (Argument Injection Vulnerability) against our honeypot sensors starting today, June 7th. Vulnerability affects PHP running on Windows.
Patches released June 6th: https://t.co/jM5HgGUZJF
Exploit PoC is public.
Greynoise researchers also reported malicious attempts of exploitation of the CVE-2024-4577.
“As of this writing, it has been verified that when the Windows is running in the following locales, an unauthorized attacker can directly execute arbitrary code on the remote server:
- Traditional Chinese (Code Page 950)
- Simplified Chinese (Code Page 936)
- Japanese (Code Page 932)
For Windows running in other locales such as English, Korean, and Western European, due to the wide range of PHP usage scenarios, it is currently not possible to completely enumerate and eliminate all potential exploitation scenarios.” continues the advisory. “Therefore, it is recommended that users conduct a comprehensive asset assessment, verify their usage scenarios, and update PHP to the latest version to ensure security.”
XAMPP Users are vulnerable due to a default configuration that exposes the PHP binary. Although XAMPP has not yet released an update for this vulnerability, DEVCORE provided instructions to mitigate the risk of attacks.
The experts recommend administrators of systems that cannot be upgraded and users of EoL versions, to apply a mod_rewrite rule to block attacks:
RewriteEngine On
RewriteCond %{QUERY_STRING} ^%ad [NC]
RewriteRule .? – [F,L]XAMPP users should find the ‘ScriptAlias’ directive in the Apache configuration file (C:/xampp/apache/conf/extra/httpd-xampp.conf) and comment it out.
“It is strongly recommended that all users upgrade to the latest PHP versions of 8.3.8, 8.2.20, and 8.1.29.” concludes the advisory. “However, since PHP CGI is an outdated and problematic architecture, it’s still recommended to evaluate the possibility of migrating to a more secure architecture such as Mod-PHP, FastCGI, or PHP-FPM.”
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