5.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
4.3 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:M/Au:N/C:P/I:N/A:N
0.003 Low
EPSS
Percentile
64.5%
There’s a possible information leak / session hijack vulnerability in Rack. Attackers may be able to find and hijack sessions by using timing attacks targeting the session id. Session ids are usually stored and indexed in a database that uses some kind of scheme for speeding up lookups of that session id. By carefully measuring the amount of time it takes to look up a session, an attacker may be able to find a valid session id and hijack the session.
The session id itself may be generated randomly, but the way the session is indexed by the backing store does not use a secure comparison.
The session id stored in a cookie is the same id that is used when querying the backing session storage engine. Most storage mechanisms (for example a database) use some sort of indexing in order to speed up the lookup of that id. By carefully timing requests and session lookup failures, an attacker may be able to perform a timing attack to determine an existing session id and hijack that session.
The 1.6.12 and 2.0.8 releases are available at the normal locations.
There are no known workarounds.
To aid users who aren’t able to upgrade immediately we have provided patches for
the two supported release series. They are in git-am format and consist of a
single changeset.
Thanks Will Leinweber for reporting this!
lists.opensuse.org/opensuse-security-announce/2020-02/msg00016.html
www.openwall.com/lists/oss-security/2019/12/18/2
www.openwall.com/lists/oss-security/2019/12/18/3
www.openwall.com/lists/oss-security/2019/12/19/3
www.openwall.com/lists/oss-security/2020/04/08/1
www.openwall.com/lists/oss-security/2020/04/09/2
github.com/advisories/GHSA-hrqr-hxpp-chr3
github.com/rack/rack/commit/7fecaee81f59926b6e1913511c90650e76673b38
github.com/rack/rack/security/advisories/GHSA-hrqr-hxpp-chr3
github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2019-16782.yml
lists.fedoraproject.org/archives/list/[email protected]/message/HZXMWILCICQLA2BYSP6I2CRMUG53YBLX/
nvd.nist.gov/vuln/detail/CVE-2019-16782
5.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
4.3 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:M/Au:N/C:P/I:N/A:N
0.003 Low
EPSS
Percentile
64.5%