Vulnerability in F5 Big-Ip Access Policy Manager
CVE-2019-1559
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).
EPSS: 0.171 (96.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- F5 Big-ip_access_policy_manager
- F5 Big-ip_advanced_firewall_manager
- F5 Big-ip_analytics
- F5 Big-ip_application_acceleration_manager
- F5 Big-ip_application_security_manager
- F5 Big-ip_domain_name_system
- F5 Big-ip_edge_gateway
- F5 Big-ip_fraud_protection_service
- F5 Big-ip_global_traffic_manager
- F5 Big-ip_link_controller
Weakness classification (CWE)
Public proof-of-concept exploits
References
- openssl-security@openssl.org (VDB Entry, Third Party Advisory, vdb-entry, x_refsource_BID)
- openssl-security@openssl.org (vendor-advisory, Third Party Advisory, x_refsource_GENTOO)
- openssl-security@openssl.org (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- openssl-security@openssl.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
- openssl-security@openssl.org (vendor-advisory, Third Party Advisory, x_refsource_DEBIAN)
- openssl-security@openssl.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
- openssl-security@openssl.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
- openssl-security@openssl.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
- openssl-security@openssl.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
- openssl-security@openssl.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
Frequently asked questions
- What is CVE-2019-1559?
- CVE-2019-1559 is a medium-severity vulnerability in F5 Big-Ip Access Policy Manager, classified under Observable Discrepancy. CVSS score: 5.9/10. Published 2019-02-27.
- How severe is CVE-2019-1559?
- Medium severity. CVSS v3 base score is 5.9 out of 10.
- Is CVE-2019-1559 known to be exploited?
- 6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.