ALAS-2017-898


Amazon Linux AMI Security Advisory: ALAS-2017-898
Advisory Release Date: 2017-10-03 11:00 Pacific
Severity: Medium

Issue Overview:

A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210 )

It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515 )

It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009 )

It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011 )

It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012 )


Affected Packages:

openssh


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

New Packages:
i686:
    openssh-ldap-7.4p1-11.68.amzn1.i686
    pam_ssh_agent_auth-0.10.3-1.11.68.amzn1.i686
    openssh-cavs-7.4p1-11.68.amzn1.i686
    openssh-7.4p1-11.68.amzn1.i686
    openssh-debuginfo-7.4p1-11.68.amzn1.i686
    openssh-keycat-7.4p1-11.68.amzn1.i686
    openssh-server-7.4p1-11.68.amzn1.i686
    openssh-clients-7.4p1-11.68.amzn1.i686

src:
    openssh-7.4p1-11.68.amzn1.src

x86_64:
    openssh-ldap-7.4p1-11.68.amzn1.x86_64
    openssh-server-7.4p1-11.68.amzn1.x86_64
    openssh-7.4p1-11.68.amzn1.x86_64
    openssh-keycat-7.4p1-11.68.amzn1.x86_64
    pam_ssh_agent_auth-0.10.3-1.11.68.amzn1.x86_64
    openssh-cavs-7.4p1-11.68.amzn1.x86_64
    openssh-debuginfo-7.4p1-11.68.amzn1.x86_64
    openssh-clients-7.4p1-11.68.amzn1.x86_64