THREATPORT/VULNERABILITY/CVE-2019-1559
MEDIUM SEVERITY

CVE-2019-1559

Openssl vulnerability

CVSS
5.9
EPSS
17.1%
EPSS pct
97th
Exploited
No known
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).
Affected vendor
Openssl
Affected product
Openssl
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness type (CWE)
Published
2019-02-27

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, high attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to confidentiality.

Its EPSS score of 17.1% reflects a moderate probability of exploitation activity in the wild over the next 30 days, placing it above 97% of all scored CVEs.

Check your external exposure to CVE-2019-1559

  • Confirm whether Openssl Openssl is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2019-1559.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2019-1559

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2019-1559 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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