Incident: Failure to Disable SMB Service in OS X 10.7 Lion

Published Date: 2011-12-20

Postmortem Analysis
Timeline 1. The software failure incident happened during the upgrade from OS X 10.6 to OS X 10.7 Lion, which was reported in an article published on 2011-12-20 [54570]. Therefore, the software failure incident occurred in December 2011.
System The system that failed in the software failure incident described in Article 54570 is: 1. OS X 10.7 Lion - Specifically, the SMB service authentication in OS X 10.7 Lion failed for some users after upgrading from OS X 10.6 [54570].
Responsible Organization 1. In-house developed suite by Apple due to changes in licensing for Samba [54570]
Impacted Organization 1. Individual users who upgraded from OS X 10.6 to OS X 10.7 Lion and had the SMB service enabled but were unable to disable it for their accounts due to authentication issues [54570].
Software Causes 1. Incompatibility with how the SMB configuration in OS X Lion was authenticating with the system directory due to the switch from the open source Samba suite to an in-house developed suite [54570].
Non-software Causes 1. Incompatibility with how the SMB configuration in Lion is authenticating with the system directory due to changes in licensing for Samba, leading to problems when used for the different software in Lion [54570].
Impacts 1. Users who had upgraded from OS X 10.6 to OS X 10.7 Lion experienced issues with disabling the SMB service for individual accounts, as the system incorrectly claimed the password was incorrect when attempting to turn off SMB sharing [54570].
Preventions 1. Properly testing the compatibility of the SMB configuration in OS X Lion with existing user account settings could have prevented the software failure incident [54570]. 2. Conducting thorough compatibility testing between the new in-house developed suite for Windows file sharing in OS X Lion and existing configurations from OS X Snow Leopard could have identified potential issues before the upgrade [54570].
Fixes 1. Switching the entries for the account's authentication authority configuration in the Directory Utility application could fix the software failure incident [54570].
References 1. Apple Discussion poster SanderFromH 2. Directory Utility application 3. CNET Mac forums 4. Twitter 5. System/Library/CoreServices/ folder

Software Taxonomy of Faults

Category Option Rationale
Recurring one_organization (a) The software failure incident related to the inability to disable SMB service after upgrading from OS X 10.6 to OS X 10.7 Lion has happened within the same organization, Apple. This incident occurred due to changes in the SMB configuration in OS X Lion, where Apple switched from the open-source Samba suite to an in-house developed suite. This change led to authentication issues when trying to disable the SMB service for individual users [54570]. (b) There is no information in the provided article about the software failure incident happening at other organizations or with their products and services.
Phase (Design/Operation) design (a) The software failure incident described in Article 54570 is related to the design phase. The issue with the SMB service not being able to be disabled for individual users after upgrading from OS X 10.6 to OS X 10.7 Lion is attributed to an incompatibility with how the SMB configuration in Lion is authenticating with the system directory to grant access or account changes. This problem arose due to the switch Apple made from the open-source Samba suite to an in-house developed suite in OS X Lion, causing configurations that worked in Snow Leopard to experience issues in Lion [54570]. (b) The software failure incident is not directly related to the operation phase or misuse of the system.
Boundary (Internal/External) within_system The software failure incident described in Article 54570 is related to the boundary of the system. The issue with disabling the SMB service after upgrading from OS X 10.6 to OS X 10.7 Lion is attributed to an incompatibility with how the SMB configuration in Lion is authenticating with the system directory to grant access or account changes. This problem arose due to the switch Apple made from the open-source Samba suite to an in-house developed suite for Windows file sharing technology in OS X Lion. This change in software components led to configurations that worked in Snow Leopard experiencing odd problems when used in Lion, indicating that the failure originated within the system itself [54570].
Nature (Human/Non-human) non-human_actions (a) The software failure incident occurring due to non-human actions: The software failure incident described in Article 54570 is related to a failure in the SMB service after upgrading from OS X 10.6 to OS X 10.7 Lion. The issue arises from an incompatibility with how the SMB configuration in Lion is authenticating with the system directory to grant access or account changes. This problem is attributed to the switch made by Apple from the open-source Samba suite to an in-house developed suite due to changes in Samba's licensing. The switch to a different software suite caused configurations that worked in Snow Leopard to experience odd problems in Lion, leading to the failure in disabling the SMB service for some users [54570]. (b) The software failure incident occurring due to human actions: There is no specific mention in the article about the software failure incident being caused by human actions. The failure is primarily attributed to the incompatibility resulting from the switch in the SMB configuration due to changes in licensing and the development of a new suite by Apple [54570].
Dimension (Hardware/Software) software (a) The software failure incident occurring due to hardware: - The article does not mention any hardware-related issues contributing to the software failure incident. It primarily focuses on the incompatibility and authentication issues related to the SMB service after upgrading from OS X 10.6 to OS X 10.7 Lion [54570]. (b) The software failure incident occurring due to software: - The software failure incident in the article is primarily attributed to software-related factors. Specifically, the issue arises from an incompatibility with how the SMB configuration in OS X Lion is authenticating with the system directory, leading to problems in disabling the SMB service for individual users. This is further exacerbated by the switch from the Samba suite to an in-house developed suite by Apple, causing configurations that worked in Snow Leopard to experience issues in Lion [54570].
Objective (Malicious/Non-malicious) non-malicious (a) The software failure incident described in Article 54570 is non-malicious. The issue reported in the article is related to a bug or flaw in the software that causes users to be unable to disable the Server Message Block (SMB) service for their accounts after upgrading from OS X 10.6 to OS X 10.7 Lion. The problem arises from an incompatibility with how the SMB configuration in Lion is authenticating with the system directory, leading to users being unable to turn off SMB even when entering the correct password. This issue is attributed to changes in the software configuration when Apple switched from the open-source Samba suite to an in-house developed suite due to licensing changes. The article provides a detailed procedure to address the problem by switching entries in the account's authentication authority configuration, indicating a technical glitch rather than a malicious attack [54570].
Intent (Poor/Accidental Decisions) accidental_decisions The software failure incident described in Article 54570 seems to be related to accidental_decisions. The issue with the inability to disable the SMB service for individual users after upgrading to OS X 10.7 Lion appears to stem from an incompatibility caused by Apple switching its windows file sharing technology from the open source Samba suite to an in-house developed suite due to changes in licensing for Samba. This unintended consequence of the switch led to configurations that worked in Snow Leopard experiencing problems in Lion. The need to switch entries for account authentication authority configuration as a workaround further supports the idea that the failure was due to unintended decisions or mistakes rather than deliberate poor decisions.
Capability (Incompetence/Accidental) accidental (a) The software failure incident described in the article is not related to development incompetence. It is primarily due to an incompatibility issue arising from changes made in the software when transitioning from OS X 10.6 to OS X 10.7 Lion. The issue stems from the switch in the windows file sharing technology from the open-source Samba suite to an in-house developed suite by Apple. This change led to configurations that worked in Snow Leopard experiencing problems when used in Lion. The solution provided involves switching entries in the account's authentication authority configuration to resolve the problem [54570]. (b) The software failure incident is accidental in nature as it is a result of unintended consequences of the changes made in the software during the transition from one version to another. The issue with disabling the SMB service for individual users in OS X 10.7 Lion occurs due to the system incorrectly claiming that the password provided is incorrect, thus keeping SMB enabled. This unintended behavior is a side effect of the changes made in the software, leading to the need for a workaround to address the problem [54570].
Duration temporary The software failure incident described in Article #54570 seems to be temporary. Users were experiencing issues with disabling the SMB service after upgrading from OS X 10.6 to OS X 10.7 Lion. The problem was related to an incompatibility with how the SMB configuration in Lion was authenticating with the system directory, possibly due to the switch from the open source Samba suite to an in-house developed suite. The article provides a workaround for users to switch entries in their account's authentication authority configuration to resolve the issue, indicating that the problem was not permanent but rather specific to certain circumstances introduced by the software upgrade.
Behaviour crash, omission, other (a) crash: The article describes a software failure incident where users upgrading from OS X 10.6 to OS X 10.7 Lion experienced issues with disabling the Server Message Block (SMB) service for individual users. When users tried to disable SMB by entering their passwords, the system claimed the incorrect password was given, and kept SMB enabled, indicating a failure in the system's state and functionality [54570]. (b) omission: The software failure incident mentioned in the article involves the omission of the system to perform the intended function of disabling the SMB service for individual users. Users were unable to turn off SMB sharing even after entering their passwords, which should have allowed them to make the necessary changes, indicating an omission in the system's behavior [54570]. (c) timing: The article does not mention any timing-related failures where the system performed its intended functions either too late or too early. (d) value: The software failure incident discussed in the article does not involve the system performing its intended functions incorrectly. (e) byzantine: The software failure incident described in the article does not exhibit behaviors of inconsistency or erratic responses that would classify it as a byzantine failure. (f) other: The other behavior observed in this software failure incident is the system's incorrect response to valid user passwords when attempting to disable the SMB service. Despite entering the correct password that allowed users to log into their accounts, the system claimed the password was incorrect when trying to disable SMB, leading to an unexpected and unexplained behavior [54570].

IoT System Layer

Layer Option Rationale
Perception None None
Communication None None
Application None None

Other Details

Category Option Rationale
Consequence delay, unknown (a) unknown (b) unknown (c) unknown (d) The software failure incident described in the article did not result in any direct harm to people or loss of life. Instead, it mainly affected users' ability to disable the SMB service on their accounts after upgrading to OS X 10.7 Lion [54570]. (e) The software failure incident caused users to experience delays in being able to disable the SMB service on their accounts as intended. Users were unable to turn off SMB even after entering their passwords, leading to a delay in resolving the issue [54570]. (f) unknown (g) The article did not mention any real observed consequences of the software failure incident. It focused on providing a solution to the issue rather than discussing any significant impacts on users or non-human entities [54570]. (h) unknown (i) unknown
Domain information (a) The software failure incident discussed in the article is related to the information industry. The issue specifically pertains to file sharing protocols between Mac and Windows machines, which are essential for sharing information and data between different systems [54570].

Sources

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