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AUSCERT External Security Bulletin Redistribution
ESB-2019.0880
MSA-19-0004: "Log in as" functionality exposed to JavaScript
risk on other users' Dashboards
19 March 2019
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AusCERT Security Bulletin Summary
---------------------------------
Product: Moodle
Publisher: Moodle
Operating System: Windows
UNIX variants (UNIX, Linux, OSX)
Impact/Access: Execute Arbitrary Code/Commands -- Existing Account
Resolution: Mitigation
CVE Names: CVE-2019-3847
Original Bulletin:
https://moodle.org/mod/forum/discuss.php?d=384010&parent=1547742
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MSA-19-0004: "Log in as" functionality exposed to JavaScript risk on other
users' Dashboards
Tuesday, 19 March 2019, 11:06 AM
Users with the "login as other users" capability (such as administrators/
managers) can access other users' Dashboards, but the JavaScript those other
users may have added to their Dashboard was not being escaped when being viewed
by the user logging in on their behalf.
Please note that for versions 3.1 and 3.4 only, this fix removes access to
other users' Dashboards while using the login-as functionality. Versions 3.5
and 3.6 have additional sanitizing implemented, which allowed the risk to be
removed while retaining Dashboard access. If you require access to Dashboards
through the login-as feature, we recommend upgrading to Moodle 3.5 or above
(noting that 3.1 and 3.4 will also no longer receive security updates after
their next releases in May 2019).
Severity/Risk: Serious
Versions affected: 3.6 to 3.6.2, 3.5 to 3.5.4, 3.4 to 3.4.7, 3.1 to 3.1.16 and
earlier unsupported versions
Versions fixed: 3.6.3, 3.5.5, 3.4.8 and 3.1.17
Reported by: Daniel Thatcher
Workaround: Use incognito/private browsing mode when using the "Log in as"
functionality, then close the private window
before logging back in as your own user, to
minimise session or cookie related risks.
Alternatively, avoid visiting the Dashboard
when logged in as other users until patch is
applied.
CVE identifier: CVE-2019-3847
Changes (master): http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-63786
Tracker issue: MDL-63786 "Log in as" functionality exposed to JavaScript risk
on other users' Dashboards
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