-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

===========================================================================
                         AUSCERT Security Bulletin

                               ASB-2017.0203
          Code execution with system privileges in iOS and MacOS
                             21 November 2017

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

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

Product:              iOS
                      MacOS
Operating System:     Apple iOS
                      Mac OS
Impact/Access:        Root Compromise -- Existing Account
Resolution:           Patch/Upgrade
CVE Names:            CVE-2017-13833 CVE-2017-13829 
Member content until: Thursday, December 21 2017

OVERVIEW

        A vulnerability was addressed in iOS 11.1.2 and MacOS 10.13.1 which
        may have enabled arbitrary code execution with system privileges. [1]


IMPACT

        The vendor has provided the following details regarding these issues:
        
        "Impact: An application may be able to execute arbitrary code with
        system privileges.
        
        Description: A memory corruption issue was addressed with improved
        memory handling." [1]
        
        Zero Day Initiative adds:
        "This vulnerability allows local attackers to escalate privileges on
        vulnerable installations of Apple macOS. An attacker must first obtain
        the ability to execute low-privileged code on the target system in
        order to exploit this vulnerability.
        
        The specific flaw exists within the nsurlstoraged service. The issue
        results from the lack of proper validation of the length of
        user-supplied data prior to copying it to a heap-based buffer.
        An attacker can leverage this vulnerability to escalate privileges
        under the context of the current service." [2]
        
        The other issue is similar, but with one difference:
        "The issue results from the lack of proper validation of a reference
        count, which can result in an integer overflow when incrementing it."
        [3]


MITIGATION

        The vendor advises to update to the latest versions of the software.
        [1] [4]


REFERENCES

        [1] About the security content of iOS 11
            https://support.apple.com/en-us/HT208112

        [2] Zero Day Initiative: nsurlstoraged Heap-based Buffer Overflow
            Privilege Escalation Vulnerability
            http://www.zerodayinitiative.com/advisories/ZDI-17-924/

        [3] Zero Day Initiative: Apple macOS nsurlstoraged Integer Overflow
            Privilege Escalation Vulnerability
            http://www.zerodayinitiative.com/advisories/ZDI-17-925/

        [4] About Apple security updates
            https://support.apple.com/en-au/HT201222

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)
                AusCERT personnel answer during Queensland business hours 
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967
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=eqKv
-----END PGP SIGNATURE-----