Incident: Twitter Outage: Date Bug Causes Service Disruption on Android.

Published Date: 2014-12-29

Postmortem Analysis
Timeline 1. The software failure incident happened on December 29, 2014. [56557]
System 1. Twitter's Android app and mobile website 2. Twitter's API 3. Coding logic related to date representation in the software [56557]
Responsible Organization 1. A bug in a line of code caused by the developer's error in specifying the year in the software led to the software failure incident [56557].
Impacted Organization 1. Users of Twitter's Android app and mobile website were impacted by the software failure incident [56557].
Software Causes 1. The software failure incident on Twitter was caused by a bug in a line of code that made the service think it was December 29, 2015, instead of the correct date in 2014 [56557]. 2. The bug was specifically related to a single character error where a 'G' was used instead of 'Y', causing the software to misinterpret the year according to ISO standards [56557].
Non-software Causes 1. The outage was caused by a bug in a line of code that made the service think it was December 29, 2015, instead of the correct date [56557]. 2. The bug was related to a single character error where a 'G' was used instead of a 'Y' in the code, causing the software to misinterpret the year [56557].
Impacts 1. Users of Twitter's Android app and mobile website were logged out and unable to log back in until the issue was fixed, causing inconvenience and disruption to their usage [56557]. 2. Visual flaws occurred, such as showing TweetDeck users that tweets were posted 365 days ago, potentially leading to confusion among users [56557]. 3. The outage lasted for over five and a half hours, affecting users during a significant portion of the early morning hours in the UK and evening hours in other time zones [56557]. 4. The software failure incident raised concerns about potential hacking activities, although it was later determined to be a result of a date bug rather than a security breach [56557].
Preventions 1. Proper input validation and error handling mechanisms could have prevented the software failure incident by ensuring that the code correctly interprets the date and year information without causing unexpected bugs [56557]. 2. Thorough testing and quality assurance procedures could have helped identify the date bug before it caused a widespread outage, allowing for timely fixes to be implemented [56557]. 3. Implementing a more robust and resilient system architecture that can handle unexpected errors or bugs without affecting the entire service could have mitigated the impact of the incident on users [56557].
Fixes 1. Implement a fix in the code to correctly handle the year calculation based on the international standards to prevent the bug that caused the service to think it was 2015 when it was still 2014 [56557].
References 1. Tweets from Twitter users such as @_Ninji and @tef [56557] 2. Screenshots of tweets and demands from the Twitter account "KingEbola" [56557]

Software Taxonomy of Faults

Category Option Rationale
Recurring one_organization (a) The software failure incident related to Twitter's service being down due to a date bug in 2014 is an example of a similar incident happening again within the same organization. This incident was caused by a bug in a line of code that made the service think it was a different date, leading to users being logged out and experiencing visual flaws [56557]. The issue stemmed from a one-character difference in coding languages, highlighting the importance of precise coding to avoid such failures in the future. (b) The article does not provide information about a similar incident happening at other organizations or with their products and services.
Phase (Design/Operation) design, operation (a) The software failure incident with Twitter was due to a bug in a line of code that caused the service to think it was December 29, 2015, instead of the correct date in 2014. This bug was a result of a design flaw in the system development where the developer had to specify which year the software should consider, leading to the wrong character being used in the code, ultimately causing the outage [56557]. (b) The software failure incident also involved operation factors as users of Twitter's Android app and mobile website were logged out without the ability to log back in until the issue was fixed. This operational failure impacted the users' experience and required intervention to resolve the issue [56557].
Boundary (Internal/External) within_system (a) The software failure incident with Twitter was within the system. The incident was caused by a bug in a line of code that made the service think it was December 29, 2015, instead of the correct date in 2014. This internal issue led to users being logged out and experiencing visual flaws on the platform [56557].
Nature (Human/Non-human) non-human_actions (a) The software failure incident occurred due to non-human actions, specifically a bug in a line of code that caused the service to think it was December 29, 2015, instead of the correct date in 2014. This bug led to users being logged out and experiencing visual flaws on the Twitter platform [56557]. (b) The software failure incident was not attributed to human actions but rather to a coding error related to the incorrect interpretation of the year in the software code. There is no indication in the article that the failure was caused by human actions such as intentional sabotage or incorrect manual changes [56557].
Dimension (Hardware/Software) software (a) The software failure incident reported in Article 56557 was due to a bug in a line of code that caused the service to think it was 29 December, 2015. This bug originated in the software itself, specifically in the code that handled date calculations. The incorrect handling of the date led to users being logged out and experiencing visual flaws on the platform [56557]. (b) The software failure incident in Article 56557 was primarily caused by a software bug related to date calculations. The issue stemmed from the incorrect representation of the year in the code, leading to users being logged out and experiencing visual glitches on the platform. The failure was not attributed to any hardware-related factors but rather to a mistake in the software logic [56557].
Objective (Malicious/Non-malicious) non-malicious (a) The software failure incident reported in the article was non-malicious. It was caused by a bug in a line of code that made the Twitter service think it was December 29, 2015, instead of the correct date in 2014. This bug led to users being logged out and experiencing visual flaws on the platform. The issue stemmed from a coding error related to specifying the year correctly based on international standards [56557]. Additionally, there were claims of responsibility for the outage by a Twitter user named "KingEbola," but the evidence suggested that the outage was not due to a malicious hack as initially speculated. The user's account was wiped of all but a single tweet after the service was restored, indicating that the incident was not a result of a deliberate attack [56557].
Intent (Poor/Accidental Decisions) accidental_decisions (a) The software failure incident related to the Twitter outage was not due to poor decisions but rather an accidental decision caused by a bug in the code. The bug in a line of code caused the service to think it was December 29, 2015, leading to users being logged out and experiencing visual flaws. The issue stemmed from a one-letter difference in coding languages, where the wrong character was used to represent the year, causing the confusion between the current year and the year of the week [56557].
Capability (Incompetence/Accidental) development_incompetence (a) The software failure incident was related to development incompetence. The outage on Twitter was caused by a bug in a line of code that made the service think it was December 29, 2015, instead of the correct date in 2014. This error stemmed from a misunderstanding of how to specify the year in coding languages, where a single character difference led to the issue. The mistake was attributed to the developer not correctly specifying whether to refer to the current year or the year of the week [56557]. (b) The software failure incident was not accidental but rather a result of a specific bug in the code that caused the service disruption on Twitter. The bug was related to how the year was interpreted in the code, leading to users being logged out and experiencing visual flaws on the platform. The incident was not a result of accidental factors but rather a direct consequence of the coding error [56557].
Duration temporary (a) The software failure incident reported in the article was temporary. The article mentions that Twitter's service was down for many users for over five and a half hours due to a bug in a line of code that caused the service to think it was December 29, 2015. The issue was fixed at 5.25 am, indicating that the failure was not permanent [56557].
Behaviour crash, omission, value, other (a) crash: The software failure incident in the article can be categorized as a crash. The bug in the line of code caused the Twitter service to be down for many users for over five and a half hours, resulting in users of the network's Android app and mobile website being logged out without the ability to log back in until it was fixed at 5.25 am [56557]. (b) omission: The software failure incident can also be categorized as an omission. Due to the bug in the code, users were logged out of the Twitter service without any ability to log back in until the issue was resolved [56557]. (c) timing: The software failure incident can be categorized as a timing issue. The bug in the code caused the service to think it was December 29, 2015, instead of the correct date, leading to users being affected during a specific time period [56557]. (d) value: The software failure incident can be categorized as a value issue. The bug in the code caused visual flaws, such as showing TweetDeck users that tweets were posted 365 days ago, which is an incorrect representation of the actual data [56557]. (e) byzantine: The software failure incident does not align with a byzantine behavior as there were no mentions of inconsistent responses or interactions in the articles. (f) other: The software failure incident can be categorized as a crash and omission, as it resulted in the system losing state and not performing its intended functions (crash) and omitting to perform its intended functions by logging users out without the ability to log back in (omission) [56557].

IoT System Layer

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

Other Details

Category Option Rationale
Consequence delay The consequence of the software failure incident reported in Article 56557 was primarily a delay. The software bug on Twitter caused the service to be down for many users for over five and a half hours, impacting their ability to log in and use the platform [56557]. Additionally, there were no reports of any other significant consequences such as harm, death, impact on basic needs, property loss, or non-human entities being affected. The incident mainly resulted in a delay in users' access to the Twitter platform.
Domain information (a) The software failure incident reported in the article was related to the information industry, specifically affecting Twitter's service [56557]. The incident caused users of the network's Android app and mobile website to be logged out due to a bug in the code that made the service think it was December 29, 2015, leading to visual flaws and login issues for users.

Sources

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