ALAS2-2019-1188

Related Vulnerabilities: CVE-2018-5407   CVE-2019-1559  

A microprocessor side-channel vulnerability was found on SMT (e.g, Hyper-Threading) architectures. An attacker running a malicious process on the same core of the processor as the victim process can extract certain secret information.(CVE-2018-5407) 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).(CVE-2019-1559)

ALAS2-2019-1188


Amazon Linux 2 Security Advisory: ALAS-2019-1188
Advisory Release Date: 2019-04-04 21:45 Pacific
Advisory Updated Date: 2019-04-17 16:59 Pacific
Severity: Medium

Issue Overview:

A microprocessor side-channel vulnerability was found on SMT (e.g, Hyper-Threading) architectures. An attacker running a malicious process on the same core of the processor as the victim process can extract certain secret information.(CVE-2018-5407)

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).(CVE-2019-1559)


Affected Packages:

openssl


Issue Correction:
Run yum update openssl to update your system.

New Packages:
aarch64:
    openssl-1.0.2k-16.amzn2.1.1.aarch64
    openssl-libs-1.0.2k-16.amzn2.1.1.aarch64
    openssl-devel-1.0.2k-16.amzn2.1.1.aarch64
    openssl-static-1.0.2k-16.amzn2.1.1.aarch64
    openssl-perl-1.0.2k-16.amzn2.1.1.aarch64
    openssl-debuginfo-1.0.2k-16.amzn2.1.1.aarch64

i686:
    openssl-1.0.2k-16.amzn2.1.1.i686
    openssl-libs-1.0.2k-16.amzn2.1.1.i686
    openssl-devel-1.0.2k-16.amzn2.1.1.i686
    openssl-static-1.0.2k-16.amzn2.1.1.i686
    openssl-perl-1.0.2k-16.amzn2.1.1.i686
    openssl-debuginfo-1.0.2k-16.amzn2.1.1.i686

src:
    openssl-1.0.2k-16.amzn2.1.1.src

x86_64:
    openssl-1.0.2k-16.amzn2.1.1.x86_64
    openssl-libs-1.0.2k-16.amzn2.1.1.x86_64
    openssl-devel-1.0.2k-16.amzn2.1.1.x86_64
    openssl-static-1.0.2k-16.amzn2.1.1.x86_64
    openssl-perl-1.0.2k-16.amzn2.1.1.x86_64
    openssl-debuginfo-1.0.2k-16.amzn2.1.1.x86_64