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                         AUSCERT Security Bulletin

                               ASB-2021.0076
                   Oracle Java SE Critical Patch Update
                               21 April 2021

===========================================================================

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

Product:          Oracle GraalVM Enterprise Edition
                  Oracle Java SE
                  Oracle Java SE Embedded
Operating System: Windows
                  UNIX variants (UNIX, Linux, OSX)
Impact/Access:    Modify Arbitrary Files   -- Remote with User Interaction
                  Denial of Service        -- Remote/Unauthenticated      
                  Access Confidential Data -- Remote/Unauthenticated      
Resolution:       Patch/Upgrade
CVE Names:        CVE-2021-23841 CVE-2021-3450 CVE-2021-2163
                  CVE-2021-2161  
Reference:        ASB-2021.0065
                  ESB-2021.1342
                  ESB-2021.0701
                  ESB-2021.0670

OVERVIEW

        Multiple vulnerabilities have been identified in :
         o Oracle GraalVM Enterprise Edition, versions 19.3.5, 20.3.1.2,
           21.0.0.2
         o Oracle Java SE, versions 7u291, 8u281, 11.0.10, 16
         o Oracle Java SE Embedded, version 8u281
        [1]


IMPACT

        The vendor has provided the following information regarding the
        vulnerabilities:
        
        "This Critical Patch Update contains 4 new security patches for
        Oracle Java SE. All of these vulnerabilities may be remotely
        exploitable without authentication, i.e., may be exploited over a
        network without requiring user credentials." [1]
        
        CVE-2021-23841
          7.5 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
        Supported versions that are affected are Oracle GraalVM Enterprise
        Edition: 19.3.5, 20.3.1.2 and 21.0.0.2. Easily exploitable
        vulnerability allows unauthenticated attacker with network access via
        HTTPS to compromise Oracle GraalVM Enterprise Edition. Successful
        attacks of this vulnerability can result in unauthorized ability to
        cause a hang or frequently repeatable crash (complete DOS) of Oracle
        GraalVM Enterprise Edition.
         Affects:
         o Oracle GraalVM Enterprise Edition Oracle GraalVM Enterprise
           Edition: 19.3.5, 20.3.1.2, 21.0.0.2
        
        CVE-2021-3450
          7.4 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
        Supported versions that are affected are Oracle GraalVM Enterprise
        Edition: 19.3.5, 20.3.1.2 and 21.0.0.2. Difficult to exploit
        vulnerability allows unauthenticated attacker with network access via
        HTTPS to compromise Oracle GraalVM Enterprise Edition. Successful
        attacks of this vulnerability can result in unauthorized creation,
        deletion or modification access to critical data or all Oracle
        GraalVM Enterprise Edition accessible data as well as unauthorized
        access to critical data or complete access to all Oracle GraalVM
        Enterprise Edition accessible data.
         Affects:
         o Oracle GraalVM Enterprise Edition Oracle GraalVM Enterprise
           Edition: 19.3.5, 20.3.1.2, 21.0.0.2
        
        CVE-2021-2161
          5.9 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
        Supported versions that are affected are Java SE: 7u291, 8u281,
        11.0.10, 16; Java SE Embedded: 8u281; Oracle GraalVM Enterprise
        Edition: 19.3.5, 20.3.1.2 and 21.0.0.2. Difficult to exploit
        vulnerability allows unauthenticated attacker with network access via
        multiple protocols to compromise Java SE, Java SE Embedded, Oracle
        GraalVM Enterprise Edition. Successful attacks of this vulnerability
        can result in unauthorized creation, deletion or modification access
        to critical data or all Java SE, Java SE Embedded, Oracle GraalVM
        Enterprise Edition accessible data.
        Note : This vulnerability applies to Java deployments that load and
        run untrusted code (e.g., code that comes from the internet) and rely
        on the Java sandbox for security. It can also be exploited by
        supplying untrusted data to APIs in the specified Component.
         Affects:
         o Java SE, Java SE Embedded, Oracle GraalVM Enterprise Edition
           Java SE: 7u291, 8u281, 11.0.10, 16; Java SE Embedded: 8u281;
           Oracle GraalVM Enterprise Edition: 19.3.5, 20.3.1.2, 21.0.0.2
        
        CVE-2021-2163
          5.3 AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
        Supported versions that are affected are Java SE: 7u291, 8u281,
        11.0.10, 16; Java SE Embedded: 8u281; Oracle GraalVM Enterprise
        Edition: 19.3.5, 20.3.1.2 and 21.0.0.2. Difficult to exploit
        vulnerability allows unauthenticated attacker with network access via
        multiple protocols to compromise Java SE, Java SE Embedded, Oracle
        GraalVM Enterprise Edition. Successful attacks require human
        interaction from a person other than the attacker. Successful attacks
        of this vulnerability can result in unauthorized creation, deletion
        or modification access to critical data or all Java SE, Java SE
        Embedded, Oracle GraalVM Enterprise Edition accessible data.
        Note : This vulnerability applies to Java deployments that load and
        run untrusted code (e.g., code that comes from the internet) and rely
        on the Java sandbox for security.
         Affects:
         o Java SE, Java SE Embedded, Oracle GraalVM Enterprise Edition
           Java SE: 7u291, 8u281, 11.0.10, 16; Java SE Embedded: 8u281;
           Oracle GraalVM Enterprise Edition: 19.3.5, 20.3.1.2, 21.0.0.2


MITIGATION

        Oracle states:
        
        "Due to the threat posed by a successful attack, Oracle strongly
        recommends that customers apply CPU fixes as soon as possible. Until
        you apply the CPU fixes, it may be possible to reduce the risk of
        successful attack by blocking network protocols required by an
        attack. For attacks that require certain privileges or access to
        certain packages, removing the privileges or the ability to access
        the packages from users that do not need the privileges may help
        reduce the risk of successful attack. Both approaches may break
        application functionality, so Oracle strongly recommends that
        customers test changes on non-production systems. Neither approach
        should be considered a long-term solution as neither corrects the
        underlying problem." [1]


REFERENCES

        [1] Oracle Critical Patch Update Advisory - April 2021
            https://www.oracle.com/security-alerts/cpuapr2021.html

        [2] Text Form of Oracle Critical Patch Update - April 2021 Risk
            Matrices
            https://www.oracle.com/security-alerts/cpuapr2021verbose.html

AusCERT has made every effort to ensure that the information contained
in this document is accurate.  However, the decision to use the information
described is the responsibility of each user or organisation. The decision to
follow or act on information or advice contained in this security bulletin is
the responsibility of each user or organisation, and should be considered in
accordance with your organisation's site policies and procedures. AusCERT
takes no responsibility for consequences which may arise from following or
acting on information or advice contained in this security bulletin.

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
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                On call after hours for member emergencies only.
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