CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
77.7%
Symfony 2.7.0 to 2.7.47, 2.8.0 to 2.8.40, 3.3.0 to 3.3.16, 3.4.0 to 3.4.10, and 4.0.0 to 4.0.10 versions of the Symfony http-foundation component are affected by this security issue.
The issue has been fixed in Symfony 2.7.48, 2.8.41, 3.3.17, 3.4.11, and 4.0.11. 4.1.0 has also been fixed before its final release.
Note that no fixes are provided for Symfony 3.0, 3.1, and 3.2 as they are not maintained anymore.
The PDOSessionHandler
class allows to store sessions on a PDO connection. Under some configurations (see below) and with a well-crafted payload, it was possible to do a denial of service on a Symfony application without too much resources.
An application is vulnerable when:
It is using PDOSessionHandler
to store its sessions;
And it uses MySQL as a backend for sessions managed by PDOSessionHandler
;
And the SQL mode does not contain STRICT_ALL_TABLES
or STRICT_TRANS_TABLES
(check via SELECT @@sql_mode
).
When an application has this configuration, doing a denial of service is made easier as a well-crafted session leads to an infinite loop in the code.
We fixed this issue by avoiding the inifinite loop.
I would like to thank Federico Stange for reporting this security issue and for working with us trying to figure out when this issue occurred, Nicolas Grekas for working on a fix, and the Symfony Core Team for reviewing the patch.
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Published in #Security Advisories
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
77.7%