New PHP Vulnerability Exposes Windows Servers to Remote Code Execution
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 article551 words · extracted from thehackernews.com · click to collapse
Ravie LakshmananJun 08, 2024Vulnerability / Programming
Details have emerged about a new critical security flaw impacting PHP that could be exploited to achieve remote code execution under certain circumstances.
The vulnerability, tracked as CVE-2024-4577, has been described as a CGI argument injection vulnerability affecting all versions of PHP installed on the Windows operating system.
According to DEVCORE security researchers, the shortcoming makes it possible to bypass protections put in place for another security flaw, CVE-2012-1823.
"While implementing PHP, the team did not notice the Best-Fit feature of encoding conversion within the Windows operating system," security researcher Orange Tsai said.
"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."
Following responsible disclosure on May 7, 2024, a fix for the vulnerability has been made available in PHP versions 8.3.8, 8.2.20, and 8.1.29.
DEVCORE has warned that all XAMPP installations on Windows are vulnerable by default when configured to use the locales for Traditional Chinese, Simplified Chinese, or Japanese.
The Taiwanese company is also recommending that administrators move away from the outdated PHP CGI altogether and opt for a more secure solution such as Mod-PHP, FastCGI, or PHP-FPM.
"This vulnerability is incredibly simple, but that's also what makes it interesting," Tsai said. "Who would have thought that a patch, which has been reviewed and proven secure for the past 12 years, could be bypassed due to a minor Windows feature?"
The Shadowserver Foundation, in a post shared on X, said it has already detected exploitation attempts involving the flaw against its honeypot servers within 24 hours of public disclosure.
watchTowr Labs said it was able to devise an exploit for CVE-2024-4577 and achieve remote code execution, making it imperative that users move quickly to apply the latest patches.
"A nasty bug with a very simple exploit," security researcher Aliz Hammond said.
"Those running in an affected configuration under one of the affected locales – Chinese (simplified, or traditional) or Japanese – are urged to do this as fast as humanely possible, as the bug has a high chance of being exploited en-mass due to the low exploit complexity."
Update
Attack surface management company Censys said it identified about 458,800 exposures of potentially vulnerable PHP instances as of June 9, 2024, most of which are located in the U.S. and Germany. But it also noted that the number is likely an "overestimate of the true impact of this vulnerability," given it cannot detect when CGI mode is enabled.
According to estimates shared by Wiz, 34% of cloud environments have Windows resources running vulnerable versions of PHP.
The development comes as Imperva warned of TellYouThePass ransomware actors actively exploiting the PHP flaw to deliver a .NET variant of the file-encrypting malware by means of an HTML Application ("dd3.hta") payload.
"The initial infection is performed with the use of an HTA file (dd3.hta), which contains a malicious VBScript," the company noted. "The VBScript contains a long base64 encoded string, which when decoded reveals bytes of a binary, which are loaded into memory during runtime."
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