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cvelistOpensslCVELIST:CVE-2019-1559
HistoryFeb 26, 2019 - 12:00 a.m.

CVE-2019-1559 0-byte record padding oracle

2019-02-2600:00:00
openssl
www.cve.org
4

6.2 Medium

AI Score

Confidence

High

0.01 Low

EPSS

Percentile

83.8%

If an application encounters a fatal protocol error and then calls SSL_shutdown() twice (once to send a close_notify, and once to receive one) then OpenSSL can respond differently to the calling application if a 0 byte record is received with invalid padding compared to if a 0 byte record is received with an invalid MAC. If the application then behaves differently based on that in a way that is detectable to the remote peer, then this amounts to a padding oracle that could be used to decrypt data. In order for this to be exploitable “non-stitched” ciphersuites must be in use. Stitched ciphersuites are optimised implementations of certain commonly used ciphersuites. Also the application must call SSL_shutdown() twice even if a protocol error has occurred (applications should not do this but some do anyway). Fixed in OpenSSL 1.0.2r (Affected 1.0.2-1.0.2q).

CNA Affected

[
  {
    "product": "OpenSSL",
    "vendor": "OpenSSL",
    "versions": [
      {
        "status": "affected",
        "version": "Fixed in OpenSSL 1.0.2r (Affected 1.0.2-1.0.2q)"
      }
    ]
  }
]

References