Operating System:

[Ubuntu]

Published:

27 January 2021

Protect yourself against future threats.

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.0287
                     USN-4705-1: Sudo vulnerabilities
                              27 January 2021

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Sudo
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Root Compromise          -- Existing Account
                   Access Confidential Data -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-23239 CVE-2021-3156 

Reference:         ESB-2021.0281

Original Bulletin: 
   https://ubuntu.com/security/notices/USN-4705-1

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USN-4705-1: Sudo vulnerabilities
26 January 2021

Several security issues were fixed in Sudo.
Releases

  o Ubuntu 20.10
  o Ubuntu 20.04 LTS
  o Ubuntu 18.04 LTS
  o Ubuntu 16.04 LTS

Packages

  o sudo - Provide limited super user privileges to specific users

Details

It was discovered that Sudo incorrectly handled memory when parsing command
lines. A local attacker could possibly use this issue to obtain unintended
access to the administrator account. ( CVE-2021-3156 )

It was discovered that the Sudo sudoedit utility incorrectly handled
checking directory permissions. A local attacker could possibly use this
issue to bypass file permissions and determine if a directory exists or
not. ( CVE-2021-23239 )

Update instructions

The problem can be corrected by updating your system to the following package
versions:

Ubuntu 20.10

  o sudo - 1.9.1-1ubuntu1.1
  o sudo-ldap - 1.9.1-1ubuntu1.1

Ubuntu 20.04

  o sudo - 1.8.31-1ubuntu1.2
  o sudo-ldap - 1.8.31-1ubuntu1.2

Ubuntu 18.04

  o sudo - 1.8.21p2-3ubuntu1.4
  o sudo-ldap - 1.8.21p2-3ubuntu1.4

Ubuntu 16.04

  o sudo - 1.8.16-0ubuntu1.10
  o sudo-ldap - 1.8.16-0ubuntu1.10

In general, a standard system update will make all the necessary changes.

References

  o CVE-2021-3156
  o CVE-2021-23239

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