Issue summary: An established DTLS 1.2 association using an AEAD cipher suite
\ncan be terminated by a single unauthenticated datagram whose encrypted
\nfragment is shorter than the mandatory explicit IV and authentication tag
\noverhead.<\/p>\n
Impact summary: An attacker who can send a datagram that is routed to an
\nexisting DTLS 1.2 association can tear that association down without knowing
\nany key material. This is a Denial of Service limited to the targeted
\nassociation. There is no memory safety or confidentiality impact.<\/p>\n
CWE: CWE-1284: Improper Validation of Specified Quantity in Input<\/p>\n
Description: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher
\nsuite carries an explicit IV followed by the ciphertext and an authentication
\ntag. When decrypting such a record the record layer passed the record length to
\nthe cipher implementation before checking that the record was long enough to
\ncontain the explicit IV and the tag. For a record shorter than that overhead the
\ncipher implementation rejected the impossible length, and the record layer
\ntreated this as an internal failure and raised a fatal internal_error alert
\ninstead of treating the record as one that failed authentication.<\/p>\n
In TLS 1.2 the same record causes a fatal internal_error alert instead of the
\nexpected bad_record_mac alert. Since any undecryptable record already
\nterminates a TLS connection, this is a protocol conformance issue rather than
\na security issue in TLS.<\/p>\n
The fix validates the record length against the explicit IV and tag length
\nbefore any AEAD processing, so that TLS reports bad_record_mac and DTLS
\nsilently discards the record.<\/p>\n
FIPS impact: no
\nThe affected code is outside the FIPS module boundary.<\/p>\n","protected":false},"excerpt":{"rendered":"
Issue summary: An established DTLS 1.2 association using an AEAD cipher suite
\ncan be terminated by a single unauthenticated datagram whose encrypted
\nfragment is shorter than the mandatory explicit IV <\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-30629","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/30629","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=30629"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=30629"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=30629"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}