Two severe web security flaws trigger urgent patching warnings

The PHP Foundation said on X that it was releasing security patches for two critical vulnerabilities rated 9.2 out of 10 on the severity scale. Ahead of the release at 14:00 UTC (10 a.m. ET), the group said, "PHP users are encouraged to prepare to update," and that it would issue an "earlier release if details become public or active exploit evidence."

The advisory followed a report showing video of a tool called PHP2Shell running code on web servers including the latest versions of WordPress, MediaWiki, Symphony, Drupal and other PHP-based sites. Security firm watchTowr said it had confirmed the vulnerability and that it affects every version from PHP 5, released in 2004, onward. In its FAQ on the exploit, watchTowr said, "According to an unverified report, the vulnerability would let an attacker run their own code on a server running PHP, potentially taking control of it."

Another security company, Sansec, said it expects "mass attacks to start within 15 minutes of the release." Web administrators were likely to scramble to patch, and some PHP-based websites could go down briefly while that happens.

The TLS problem centered on eMudhra, an India-based certificate authority. The firm said eight of its intermediate CA certificates had been compromised and that they "chain to roots trusted by Mozilla, Microsoft, Apple and Chrome root programs and by many downstream trust stores." The issue is that private keys were weak enough to let attackers forge credentials for a range of websites and apps.

Hacker News and other reports said the compromised private key sizes ranged from three to eight bits, rather than the usual 384 bits, and that such keys could be recovered by testing just 256 possible numbers. The reports listed eMudhra's keys as 4, 56, 66, 115, 155, 156, 230 and 237.

The eMudhra certificates were widely trusted by hosts such as Cloudflare, browsers, operating systems, IoT devices and other machines that connect to the internet. Once attackers forge domain certificates, they can impersonate servers and intercept traffic. Mozilla, Google and Apple blocked the compromised certificates in their browsers. Mozilla security expert Dennis Jackson warned that a macOS utility may continue to trust them because it does not check for revocation information, a problem that applies to many other clients. eMudhra revoked the eight certificates and blamed a script used to generate them.

The biggest current risk is to VPNs, particularly where governments actively try to intercept traffic, the report said. It may also affect IoT devices, unmaintained servers and other parts of the internet. "This will be a massive cleanup job, bigger than Heartbleed," cryptography engineer Filippo Valsorda told Ars, referring to the 2014 TLS bug that caused mass attacks.