Experts warn of mass exploitation of critical PHP flaw CVE-2024
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 article606 words · extracted from securityaffairs.com · click to collapse
Threat actors exploit PHP flaw CVE-2024-4577 for remote code execution. Over 1,000 attacks detected globally.
GreyNoise researchers warn of a large-scale exploitation of a critical vulnerability, tracked as CVE-2024-4577 (CVSS 9.8), in PHP. An attacker could exploit the vulnerability to achieve remote code execution on vulnerable servers using Apache and PHP-CGI.
The flaw CVE-2024-4577 (CVSS score: 9.8) is a PHP-CGI OS Command Injection Vulnerability. The issue 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 public availability of a PoC exploit code, multiple actors are attempting to exploit it, reported Shadowserver and GreyNoise researchers.
In June, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) added the the vulnerability to its Known Exploited Vulnerabilities (KEV) catalog.
In July 2024, the Akamai Security Intelligence Response Team (SIRT) warned that multiple threat actors were exploiting the PHP vulnerability CVE-2024-4577 to deliver multiple malware families, including Gh0st RAT, RedTail cryptominers, and XMRig.
“Threat actors continued the speedy-time-from-disclosure-to-exploitation trend and were quick to leverage this new vulnerability — we observed exploit attempts targeting this PHP flaw on our honeypot network within 24 hours of its disclosure.” reported Akamai.
At the time, 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.
Akamai researchers also observed threat actors behind the DDoS botnet Muhstik exploiting this vulnerability.
Last week, Cisco Talos researchers reported that an unknown threat actor has been exploiting the flaw since as early as January 2025, predominantly targeting organizations in Japan.
Now, GreyNoise researches confirm the large scale exploitation of CVE-2024-4577 and warns that it is not limited to Japanese entities. The experts observed a surge in the attacks against the US, the UK, Singapore, Indonesia, Taiwan, Hong Kong, India, and Spain.
“GreyNoise data confirms that exploitation of CVE-2024-4577 extends far beyond initial reports. Attack attempts have been observed across multiple regions, with notable spikes in the United States, Singapore, Japan, and other countries throughout January 2025.” reads the advisory.
GreyNoise detected 1,089 unique IPs exploiting CVE-2024-4577 in January 2025, with attacks spreading beyond Japan to Singapore, Indonesia, the UK, Spain, and India. Over 43% of attacks originate from Germany and China. In February, a coordinated spike in global exploitation suggested increased automated scanning for vulnerable systems.
The company urges users to update their installations as soon as possible.
“Organizations with internet-facing Windows systems exposing PHP-CGI — especially those in these newly identified targeted regions — should follow the guidance provided by Cisco Talos and perform retro-hunts to identify similar exploitation patterns.” concludes GreyNoise.
“Identify and block malicious IPs actively targeting CVE-2024-4577. “
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(SecurityAffairs – hacking, PHP-CGI OS Command Injection Vulnerability)
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