Synopsis
The remote web server uses a version of PHP that is affected by multiple vulnerabilities.
Description
Versions of PHP 5.4.x earlier than 5.4.39, or 5.5.x earlier than 5.5.23 are exposed to the following issues :
- Multiple flaws exist related to using pathnames containing NULL bytes. A remote attacker can exploit these flaws, by combining the '\0' character with a safe file extension, to bypass access restrictions. This had been previously fixed but was reintroduced by a regression in versions 5.4+. (CVE-2006-7243, CVE-2015-4025)
- A flaw exists in the phar_parse_tarfile() function in 'ext/phar/tar.c' that is triggered when handling zero-length filenames. This may allow an attacker to corrupt memory, crashing an application or potentially allowing code execution. (CVE-2015-4021)
- A flaw exists in the multipart_buffer_headers() function in file 'rfc1867.c' due to improper handling of multipart/form-data in HTTP requests. A remote attacker can exploit this flaw to cause a consumption of CPU resources, resulting in a denial of service condition. (CVE-2015-4024)
- A security bypass vulnerability exists due to a flaw in the 'pcntl_exec' implementation that truncates a pathname upon encountering the '\x00' character. A remote attacker can exploit this, via a crafted first argument, to bypass intended extension restrictions and execute arbitrary files. (CVE-2015-4026)
- An integer overflow condition exists in the function str_repeat(). The issue is triggered due to a sign mismatch condition. This may allow a context-dependent attacker to create corrupted ZVALs, leading to memory corruption. This may result in a denial of service or potentially the execution of arbitrary code.
- An overflow condition affects the unpack() function in 'ext/standard/pack.c'. The issue is triggered as user-supplied input passed via the 'format' parameter is not properly validated. This may allow a context-dependent attacker to cause a heap-based buffer overflow, resulting in a denial of service or potentially allowing the execution of arbitrary code.
Solution
Apply the vendor patch or upgrade to PHP version 5.5.25 or later. If 5.5.x cannot be installed, 5.4.41 is also patched for these vulnerabilities.