String#unpack receives format specifiers as its parameter, and can be specified the position of parsing the data by the specifier @. If a big number is passed with @, the number is treated as the negative value, and out-of-buffer read is occurred. So, if a script accepts an external input as the argument of String#unpack, the attacker can read data on heaps. Affected versions: Ruby 2.2 series: 2.2.9 and earlier Ruby 2.3 series: 2.3.6 and earlier Ruby 2.4 series: 2.4.3 and earlier Ruby 2.5 series: 2.5.0 and earlier External References: https://www.ruby-lang.org/en/news/2018/03/28/buffer-under-read-unpack-cve-2018-8778/
Created ruby tracking bugs for this issue: Affects: fedora-all [bug 1561957]
Mitigation: Vulnerable code when String#unpack's argument is attacker controlled. In the unpack format string argemument, manual sanitization can be done by preventing the number following '@' to overflow to a negative number. See https://dev.to/sqreenio/an-in-depth-look-at-cve-2018-8878-or-why-integer-overflows-are-still-a-thing-1n01 for mitigation details.
Upstream fix : https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=62992
Statement: This issue affects the versions of ruby as shipped with Red Hat CloudForms 4. Red Hat Product Security has rated this issue as having security impact of Moderate. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/. This issue affects the versions of ruby as shipped with Red Hat Subscription Asset Manager 1. Red Hat Product Security has rated this issue as having security impact of Moderate. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
This issue has been addressed in the following products: Red Hat Software Collections for Red Hat Enterprise Linux 6 Red Hat Software Collections for Red Hat Enterprise Linux 7 Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS Via RHSA-2018:3729 https://access.redhat.com/errata/RHSA-2018:3729
This issue has been addressed in the following products: Red Hat Software Collections for Red Hat Enterprise Linux 6 Red Hat Software Collections for Red Hat Enterprise Linux 7 Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS Via RHSA-2018:3730 https://access.redhat.com/errata/RHSA-2018:3730
This issue has been addressed in the following products: Red Hat Software Collections for Red Hat Enterprise Linux 7 Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS Via RHSA-2018:3731 https://access.redhat.com/errata/RHSA-2018:3731
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2019:2028 https://access.redhat.com/errata/RHSA-2019:2028
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.5 Extended Update Support Via RHSA-2020:1963 https://access.redhat.com/errata/RHSA-2020:1963
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.4 Advanced Update Support Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions Red Hat Enterprise Linux 7.4 Telco Extended Update Support Via RHSA-2020:2212 https://access.redhat.com/errata/RHSA-2020:2212
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.6 Extended Update Support Via RHSA-2020:2288 https://access.redhat.com/errata/RHSA-2020:2288