N\u00eb implementimin e funksionit t\u00eb hasheve kriptografike SHA-3 (Keccak), i propozuar n\u00eb paket\u00ebn XKCP (eXtended Keccak Code Package), \u00ebsht\u00eb zbuluar nj\u00eb vulnerabilitet (CVE-2022-37454), q\u00eb mund t\u00eb \u00e7oj\u00eb n\u00eb mbushjen e buffers gjat\u00eb procesit t\u00eb p\u00ebrpunimit t\u00eb t\u00eb dh\u00ebnave t\u00eb caktuara. Problemi shkaktohet nga nj\u00eb gabim n\u00eb kodin e implementimit t\u00eb ve\u00e7ant\u00eb t\u00eb SHA-3, dhe jo nga vet\u00eb algoritmi. Paketa XKCP paraqitet si implementimi zyrtar i SHA-3, zhvillohet me pjes\u00ebmarrjen e ekipit t\u00eb zhvilluesve Keccak dhe p\u00ebrdoret si baz\u00eb n\u00eb funksionet p\u00ebr pun\u00ebn me SHA-3 n\u00eb gjuh\u00eb t\u00eb ndryshme programimi (p.sh., kodi XKCP p\u00ebrdoret n\u00eb modul\u00ebn hashlib t\u00eb Python, paket\u00ebn digest-sha3 t\u00eb Ruby dhe funksionet hash_* t\u00eb PHP). <\/p>\n
Sipas deklarat\u00ebs s\u00eb k\u00ebrkuesit q\u00eb zbuloi problemin, ai arriti t\u00eb p\u00ebrdor\u00eb vulnerabilitetin p\u00ebr t\u00eb shkelur vetit\u00eb kriptografike t\u00eb funksionit t\u00eb hash-it dhe p\u00ebr t\u00eb gjetur parazgjedhjet e para dhe t\u00eb dyta, si dhe p\u00ebr t\u00eb p\u00ebrcaktuar kolizionet. P\u00ebr m\u00eb tep\u00ebr, \u00ebsht\u00eb deklaruar se \u00ebsht\u00eb krijuar nj\u00eb prototip i nj\u00eb eksploitimi, i cili mund\u00ebson ekzekutimin e kodit gjat\u00eb llogaritjes s\u00eb hash-it p\u00ebr nj\u00eb skedar t\u00eb caktuar. Potencialisht, vulnerabiliteti gjithashtu mund t\u00eb p\u00ebrdoret p\u00ebr sulme ndaj algoritmeve t\u00eb verifikimit t\u00eb n\u00ebnshkrimeve digjitale q\u00eb p\u00ebrdorin SHA-3 (p.sh., Ed448). Detajet e metodave t\u00eb kryerjes s\u00eb sulmeve planifikohen t\u00eb publikohen m\u00eb von\u00eb, pas eliminimit t\u00eb plot\u00eb t\u00eb vulnerabilitetit. <\/p>\n
Sa sa shfaqur do t\u00eb jet\u00eb e paqart\u00eb se sa e preku kjo dob\u00ebsi aplikacionet ekzistuese, pasi p\u00ebr t\u00eb shfaqur problemin n\u00eb kod, duhet t\u00eb aplikohet nj\u00eb llogaritje ciklike e hashes n\u00eb blloqe dhe nj\u00eb nga blloqet q\u00eb po p\u00ebrpunohen duhet t\u00eb ket\u00eb nj\u00eb madh\u00ebsi rreth 4 GB (jo m\u00eb pak se 2^32 - 200 byte). Kur p\u00ebrpunohen t\u00eb dh\u00ebnat nj\u00ebher\u00ebsh (pa llogaritje sekondare t\u00eb hashes n\u00eb pjes\u00eb), problemi nuk shfaqet. Si nj\u00eb metod\u00eb e thjesht\u00eb mbrojt\u00ebse, sugjerohet kufizimi i madh\u00ebsis\u00eb maksimale t\u00eb t\u00eb dh\u00ebnave q\u00eb marrin pjes\u00eb n\u00eb nj\u00eb iteracion t\u00eb vet\u00eb llogaritjes s\u00eb hashes. <\/p>\n
Dob\u00ebsia shkaktohet nga nj\u00eb gabim n\u00eb p\u00ebrpunimin bllok t\u00eb t\u00eb dh\u00ebnave t\u00eb hyrjes. P\u00ebr shkak t\u00eb krahasimit t\u00eb pavlefsh\u00ebm t\u00eb vlerave me lloj «int», p\u00ebrcaktohet nj\u00eb madh\u00ebsi e gabuar e t\u00eb dh\u00ebnave q\u00eb pritet t\u00eb p\u00ebrpunohen, duke \u00e7uar n\u00eb shkrimin e bishtit jasht\u00eb buffers t\u00eb caktuar. Sidomos, n\u00eb krahasim ishte p\u00ebrdorur shprehja «partialBlock + instance->byteIOIndex», e cila p\u00ebr vlera t\u00eb m\u00ebdha t\u00eb komponenteve \u00e7onte n\u00eb overflow t\u00eb numrit t\u00eb plot\u00eb. P\u00ebr m\u00eb tep\u00ebr, n\u00eb kod kishte nj\u00eb konvertim t\u00eb pavlefsh\u00ebm t\u00eb tipit «(unsigned int)(dataByteLen - i)», q\u00eb \u00e7onte n\u00eb overflow n\u00eb sistemet me tip size_t 64-bit. <\/p>\n