A vulnerability in PHP could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.
The vulnerability is due to a NULL pointer dereference condition that exists in the php_imap.c file of the affected software. An attacker could exploit this vulnerability by sending a message argument with an empty string to the imap_mail function on a targeted system. A successful exploit could trigger a NULL pointer dereference condition, which the attacker could use to cause the software to crash, resulting in a DoS condition.
PHP has confirmed the vulnerability and released software updates.
To exploit this vulnerability, the attacker must send a message argument to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators can help protect affected systems from external attacks by using a solid firewall strategy.
Administrators are advised to monitor affected systems.
PHP has confirmed the vulnerability at the following link: Bug #77020
PHP has released software updates at the following link: PHP Downloads
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.