{"id":105350,"date":"2022-10-21T09:36:42","date_gmt":"2022-10-21T07:36:42","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-biblioteke-s-osnovnoj-realizacziej-algoritma-sha-3"},"modified":"2022-10-21T09:36:42","modified_gmt":"2022-10-21T07:36:42","slug":"uyazvimost-v-biblioteke-s-osnovnoj-realizacziej-algoritma-sha-3","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hu\/blog\/news\/uyazvimost-v-biblioteke-s-osnovnoj-realizacziej-algoritma-sha-3","title":{"rendered":"Sebezhet\u0151s\u00e9g a SHA-3 algoritmus f\u0151 implement\u00e1ci\u00f3s k\u00f6nyvt\u00e1r\u00e1ban","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"
A SHA-3 (Keccak) cryptographic hash function implementation, proposed in the XKCP (eXtended Keccak Code Package), has revealed a vulnerability (CVE-2022-37454) that may lead to a buffer overflow when processing specifically formatted data. The problem is caused by a bug in the specific implementation of SHA-3, not a vulnerability in the algorithm itself. The XKCP package is presented as the official implementation of SHA-3, developed with the participation of the Keccak development team, and is used as the foundation in functions for working with SHA-3 in various programming languages (for example, the XKCP code is used in the Python hashlib module, the Ruby digest-sha3 package, and PHP hash_* functions). <\/p>\n
According to the researcher who identified the problem, they were able to exploit the vulnerability to break the cryptographic properties of the hash function and find first and second pre-images, as well as define collisions. Additionally, a prototype exploit has reportedly been created that allows code execution when hashing a specially crafted file. The vulnerability may also potentially be used for attacks on digital signature verification algorithms that utilize SHA-3 (for example, Ed448). Details of the attack methods are planned to be published later, after the vulnerability is addressed worldwide. <\/p>\n
A sebezhet\u0151s\u00e9g gyakorlati hat\u00e1sa a megl\u00e9v\u0151 alkalmaz\u00e1sokra m\u00e9g nem vil\u00e1gos, mivel a probl\u00e9ma megnyilv\u00e1nul\u00e1s\u00e1hoz ciklikus hash sz\u00e1m\u00edt\u00e1st kell alkalmazni blokkban, \u00e9s az egyik feldolgozott blokk m\u00e9ret\u00e9nek k\u00f6r\u00fclbel\u00fcl 4 GB-nak (legal\u00e1bb 2^32 \u2014 200 byte) kell lennie. Ha a bemeneti adatokat egyszerre dolgozz\u00e1k fel (an\u00e9lk\u00fcl, hogy a hash-t r\u00e9szekben sz\u00e1m\u00edtan\u00e1k), a probl\u00e9ma nem jelentkezik. A v\u00e9dekez\u00e9s legk\u00f6nnyebb m\u00f3djak\u00e9nt aj\u00e1nlott korl\u00e1tozni az egy iter\u00e1ci\u00f3ban r\u00e9szt vev\u0151 adatok maxim\u00e1lis m\u00e9ret\u00e9t. <\/p>\n
A sebezhet\u0151s\u00e9get a bemeneti adatok blokkban val\u00f3 feldolgoz\u00e1s\u00e1nak hib\u00e1ja okozza. A \"int\" t\u00edpus\u00fa \u00e9rt\u00e9kek k\u00f6z\u00f6tti helytelen \u00f6sszehasonl\u00edt\u00e1s miatt t\u00e9vesen meghat\u00e1roz\u00e1sra ker\u00fcl a feldolgoz\u00e1sra v\u00e1r\u00f3 adatok m\u00e9rete, ami a rendeltet\u00e9sszer\u0171 puffer t\u00fall\u00e9p\u00e9s\u00e9hez vezet. K\u00fcl\u00f6n\u00f6sen az \"partialBlock + instance->byteIOIndex\" kifejez\u00e9s haszn\u00e1lata, amely nagy \u00f6sszetev\u0151k eset\u00e9n eg\u00e9sz sz\u00e1m t\u00falfut\u00e1shoz vezetett. Ezenk\u00edv\u00fcl a k\u00f3dban helytelen t\u00edpus\u00e1talak\u00edt\u00e1s is volt: \"(unsigned int)(dataByteLen - i)\", amely a 64 bites size_t t\u00edpus\u00fa rendszereken t\u00falfut\u00e1shoz vezetett. <\/p>\n