Prabhu's Maya

Prabhu

This post is the second out of three blog posts summarizing my (Louis Jannett) research on the design, security, and privacy of real-world Single Sign-On (SSO) implementations. It is based on my master's thesis that I wrote between April and October 2020 at the Chair for Network and Data Security.

We structured this blog post series into three parts according to the research questions of my master's thesis: Single Sign-On Protocols in the Wild, PostMessage Security in Single Sign-On, and Privacy in Single Sign-On Protocols.

Overview

Part I: Single Sign-On Protocols in the Wild

Although previous work uncovered various security flaws in SSO, it did not work out uniform protocol descriptions of real-world SSO implementations. We summarize our in-depth analyses of Apple, Google, and Facebook SSO. We also refer to the sections of the thesis that provide more detailed insights into the protocol flows and messages.

Part II: PostMessage Security in Single Sign-On

It turned out that the postMessage API is commonly used in real-world SSO implementations. We introduce the reasons for this and propose security best practices on how to implement postMessage in SSO. Further, we present vulnerabilities on top-visited websites that caused DOM-based XSS and account takeovers due to insecure use of postMessage in SSO.

Part III: Privacy in Single Sign-On Protocols

Identity Providers (IdPs) use "zero-click" authentication flows to automatically sign in the user on the Service Provider (SP) once it is logged in on the IdP and has consented. We show that these flows can harm user privacy and enable new targeted deanonymization attacks of the user's identity.

Introduction to XS-Leaks in Single Sign-On
XS-Leaks in Single Sign-On: Account Leakage Attack
XS-Leaks in Single Sign-On: Identity Leakage Attack
Automatic Sign-In and Session Management Practices in the Wild

Introduction to XS-Leaks in Single Sign-On

Cross-site leak (XS-Leak) refers to a family of browser side-channel techniques that can be used to infer and gather information about users [...]. While the deanonymization capabilities of XS-Leak attacks are only just being realized, some researchers have said the technique will soon be in the OWASP Top 10.

Source: Latest cross-site leak (XS-Leak) news | The Daily Swig

In SSO setups, redirects can leak private information about the user. Thus, we focused on XS-Leaks that detect cross-origin redirects, i.e., whether a cross-origin request returns an `HTTP/200` or `HTTP/302` response. In this post, we present an XS-Leak that is based on the Fetch API and detects cross-origin redirects with 100% accuracy. The following method expects a URL, sends a GET request, and finally returns `true` if the response is a redirect or `false` if the response is no redirect:

// let is_redirect = await xs_leak_redirect("<URL>");  async function xs_leak_redirect(url) { 	let res = await fetch(url, { 		mode: "cors", 		credentials: "include", 		redirect: "manual" 	}).then( (response) => { 		if (response.type == "opaqueredirect") { 			return true; 		} 	}).catch( (error) => { 		return false; 	}); 	return res; }

More details are provided in Section 5.1.4.1 of the thesis.

XS-Leaks in Single Sign-On: Account Leakage Attack

With the account leakage attack, the attacker can determine whether the victim has an account on a targeted SP with a certain IdP. Specifically, the attacker checks whether the victim has granted consent to the targeted SP with the IdP. This attack is scalable: The attacker can test multiple (SP, IdP) pairs and check for which pair the victim has an account on the SP. The following prerequisites must hold:

The victim visits an attacker-controlled website.
The victim is signed-in on the IdP (i.e., in Google Chrome with its Google account).
The IdP supports the standardized `prompt=none` parameter.

The attack idea is simple: Let's assume the attacker wants to know whether the victim has an account on SP `sp.com` with the IdP `idp.com`. The attacker first tricks the victim into visiting its malicious website `attacker.com`. We further assume that the victim has an active session on the IdP. Then, the attacker constructs an Authentication Request URL, as shown in the figure below. Note that the SP `sp.com` has the `client_id=superSecretClient` on the IdP, the `redirect_uri` is set to `sp.com/redirect`, and the `prompt=none` parameter is set.

From the attacker's website, a cross-origin `Fetch` request is sent to that URL as shown before. If the `prompt=none` flow is requested with established consent on the SP, the IdP returns the Authentication Response as an `HTTP/302` redirect to the `redirect_uri`. If the victim has not granted the SP's consent, the IdP returns the consent page with an `HTTP/200` response and asks the user to grant the consent. Thus, based on whether the victim has or has not an account on `sp.com`, the IdP returns an `HTTP/302` redirect or an `HTTP/200` response. Although the Same Origin Policy prevents us from viewing the response from `idp.com`, we can use the XS-Leak to detect whether a redirect was performed or not. If a redirect was performed, the victim has an account on `sp.com` with the IdP. If no redirect was performed, the victim has no account.

We tested this attack with the Apple, Google, and Facebook IdP. It only works for Google and Facebook since Apple requires user interaction in each flow. A working PoC is provided on https://xsleak.sso.louisjannett.de. If the "Start" button is clicked, the website checks if you have an account on adobe.com, ebay.com, imdb.com, medium.com, or vimeo.com using either the Google or Facebook IdP. Make sure that you are signed in at Google and Facebook before testing and enable third-party cookies.

To circumvent this attack, the IdP must return an error as `HTTP/302` redirect if the `prompt=none` flow is requested, but no consent is given. This mitigation is described in the OpenID Connect specification, but as shown, not adopted by real-world IdPs.

More details are provided in Section 5.1 of the thesis.

XS-Leaks in Single Sign-On: Identity Leakage Attack

The identity leakage attack extends the account leakage attack by the `login_hint` parameter. The attacker can determine whether the victim has a certain identity on a targeted IdP. The attacker can use this information to check if a certain person is visiting its website. Therefore, all prerequisites of the account leakage attack must hold and the IdP must support the standardized `login_hint` parameter.

Once a victim visits the malicious website, the attacker must initially guess an (SP, IdP) pair that the victim most likely gave consent to, i.e., that causes the IdP in the `prompt=none` flow to return a redirect to `sp.com/redirect`. The attacker can use the account leakage attack to determine such a pair by testing the most-popular SPs and IdPs. Then, a new Authentication Request is created, and the `login_hint` parameter is set to the email address of the victim, i.e., `alice@example.com`. The attacker sends the Fetch request and determines whether the IdP returns an `HTTP/302` redirect or an `HTTP/200` response. If a redirect was performed, the attacker knows that the Authentication Request was valid, and thus the victim is `alice@example.com`. If no redirect was performed, the victim is not `alice@example.com`. The success of this attack depends on whether the attacker can guess (or eventually knows) an (SP, IdP) pair that the targeted victim gave consent to.

We tested this attack with the Apple, Google, and Facebook IdP. It only works for Google since Apple does not support the `prompt=none` flow, and Facebook does not support the `login_hint` parameter. We discovered that the `login_hint` parameter must contain a valid email address registered at Google. Otherwise, this parameter is ignored.

To mitigate this leakage, the IdP must return an error as `HTTP/302` redirect if a `login_hint` parameter is queried that the user does not own. We did not find any information about the `login_hint` parameter in the OpenID Connect specification that proposes guidelines for this scenario.

More details are provided in Sections 5.1 of the thesis.

Following the observations of the account leakage and identity leakage attacks, we analyzed "zero-click" SSO flows in terms of automatic sign-in features provided by the IdPs with their SDKs. We found that under certain assumptions, the SDKs can be configured to automatically sign in the user on the SP even though the user did not click on the sign-in button and may not notice the sign-in process.

Google and Facebook support automatic sign-in with their SSO SDKs: Google Sign-In, Google One Tap, and Facebook Login. They follow a similar approach: The user visits the SP website that integrates and initializes the SDK with automatic sign-in enabled. Suppose the user has an active session on the IdP, valid consent for the SP, and third-party cookies enabled. In that case, the SDK first retrieves a logout state from browser storage to determine whether the user signed out previously using the SDK's sign-out method. If the logout state is set to false or does not exist, the SDK returns the Authentication Response to the SP website, i.e., to a registered callback. If it is set to true, the SDK does not proceed with the automatic sign-in and instead requires the user to click on the sign-in button. Thus, the execution of the automatic sign-in flow depends on the stored logout state. If the browser storage is cleared (i.e., cookies are deleted or a private window is opened), the logout state does not exist, and thus the automatic sign-in is enabled.

Note that the logout state is only a feature provided by the SDKs to stop unwanted sign-in operations on the SP. They do not prevent the SP from secretly receiving tokens from the IdP. If the SP does not use the SDK's sign-out method, the logout state will never be set to true. Alternatively, the SP may manually request the tokens from the IdP in the background without paying attention to any logout state. Note that this automatic sign-in flow is different than the standardized `prompt=none` flow because it returns the tokens in the background (i.e., via Fetch requests), whereas the `prompt=none` flow requires a redirect that is in some form visible to the user.

Google and Facebook use different approaches to receive the Authentication Response in the background. Google sends a `getTokenResponse` RPC from the SP website to its proxy iframe and receives the tokens with postMessage. Facebook issues a simple CORS request and receives the tokens in the CORS response.

For instance, SPs can send the following CORS request with the Fetch API to Facebook:

GET /x/oauth/status?client_id=<CLIENT_ID> HTTP/1.1 Host: www.facebook.com Origin: https://sp.com Cookie: c_user=REDACTED; xs=REDACTED;

If the user has an active session at Facebook (i.e., cookies are set) and valid consent, Facebook responds with a CORS response and explicitly allows the SP to read the `fb-ar` header that contains the tokens:

HTTP/1.1 200 OK Access-Control-Allow-Origin: https://sp.com Access-Control-Allow-Credentials: true Access-Control-Expose-Headers: fb-ar,fb-s fb-s: connected fb-ar: {"user_id": "REDACTED", "access_token": "REDACTED", "signed_request": "REDACTED"}

We tested the automatic sign-in on top-visited SPs and found that some of them implement it as expected. For instance, `change.org` supports automatic sign-in with Facebook: First, we open `change.org` without being logged in on Facebook. Thus, we are not signed-in automatically. Then, we log in on Facebook and reload `change.org`. As shown, `change.org` uses the CORS request to receive the tokens from Facebook and finally logs us in. The user interface does not indicate that we were just signed in. Only the small profile picture in the top right corner is added to the UI.

More details and examples of automatic sign-in flows are provided in Section 5.3 of the thesis.

Acknowledgments

My thesis was supervised by Christian Mainka, Vladislav Mladenov, and Jörg Schwenk. Huge "thank you" for your continuous support, advice, and dozens of helpful tips.

Also, special thanks to Lauritz for his feedback on this post and valuable discussions during the research. Check out his blog post series on Real-life OIDC Security as well.

Authors of this Post

Louis Jannett

Introduction

The OpenID Connect protocol framework defines three basic flows, Authorization Code Flow (or just Code Flow), Implicit Flow, and Hybrid Flow. OAuth 2.0, which is the foundation of OpenID Connect, introduces several extensions. One of the latest extensions is Code Flow with PKCE (Proof Key for Code Exchange, RFC7636).

Compliance with the specification requirements is essential for application security. Settings and parameter conditions are changed. For example, in Code Flow, a nonce parameter in the Authentication Request is optional but required for the Implicit Flow. The developers have to deal with such changes. They end up implementing several code branches and various state machines. The implementation's code complexity naturally increases if it supports more features and extensions. This complexity implies that minor changes with only one specific flow in mind can introduce a security issue in another flow.

Various well-known attacks are published in different papers and several mitigations are mentioned in best practice guides. One tool, which can perform the fully automated evaluation of services with generic attack vectors, is PrOfESSOS.

PrOfESSOS

PrOfESSOS is our evaluation as a Service (EaaS) security tool. We have implemented significant improvements into it over the past few years. The latest version can simulate a malicious RP that can carry out the attacks against an OP. In addition, PrOfESSOS can simulate an honest and a malicious OP to perform Single-Phase and Cross-Phase attacks. A penetration tester can access the RESTful API directly or the Web UI to start an evaluation.

Supported attacks on Relying Parties

Single Phase	# Attack Patterns	Cross Phase	# Attack Patterns
ID Spoofing	12	Issuer Confusion	1
Replay Attack	6	IdP Confusion	1
Key Confusion	13	Malicious Endpoint Attack	1
Signature Manipulation	4	Session Overwriting	2
Cross Site Request Forgery	3
Token Recipient Confusion	3
Token Substitution	2

Supported attacks on OpenID Provider

Attack	# Attack Patterns
Authorization Code Reuse and Substitution	5
Redirect URI Manipulation	15
Open Redirector	1
Client Authentication Bypass	15
Message Flow Confusion	2
PKCE Downgrade Attack	5
Sub Claim Spoofing	5

The Lab Environment

Overview

A developer or security researcher needs a running web application to start an evaluation. One way to create an analysis is to execute the web application and evaluation tools on a local development machine. This approach might be a practical compromise for small-scale projects. For multiple instances of applications with different configurations, this approach can be cumbersome. Docker containers can help here. Various RP and OP already offer a container setup, or there are examples of creating Dockerfiles, at least. It is possible to have reproducible build results through the container concept. In addition, this approach enables us to store static configuration files and SQL dumps for a specific instance.

We introduced three networks running on a server for our lab environment setup. The ProfNET for all evaluation tools can be controlled and debugged from a remote client. Furthermore, we added a RPNet for all Relying Parties and an OPNet for all OpenID Provider. The MitMProxy connects the networks and the users' browser. It allows us to observe and manipulate every http(s) communication in front- and back-channel.

Setup

Server Side

It is only required to checkout the oidc-docker-libs. The docker-compose setup can be built and run with:

git clone https://github.com/RUB-NDS/oidc-docker-libs docker-compose build docker-compose up -d

The following ports are used by the lab: 8787, 9990, 8888, 8042, 8080, 8081. You should ensure that you don't have service running on those ports.

The docker-compose provides the possibility to run only a small subset, for example:

docker-compose up -d professos mitmproxy mitreid-server

Docker Structure

The basic idea of our docker containers is to build from sources in a more or less generic way. We intended that each application runs as a completely independent unit. The application configuration can be performed with build arguments, environment variables, or complete SQL dumps.

You can see that we structured a Dockerfile in four blocks:

FROM ubuntu:18.04  ARG BRANCH=v3 ARG FLOW=implicit ARG CONTROLLER_URL ARG SERVER_HOST  # Setup the application ENV APPDIR /opt/app WORKDIR ${APPDIR} RUN git clone --depth=1 --branch=$BRANCH https://github.com/YOU/YOUR_APP RUN cd YOUR_APP \     && echo config=$FLOW >> configuration_file \     && ./build  # deploy automatically created certs ARG CA_DIR="/certs" ARG CA_CERT="oidc-ca.crt" VOLUME ["$CA_DIR"]  # Configure apache or nginx COPY config/apache-ssl.conf /etc/apache2/sites-available/ssl.conf RUN sed -i "s#SERVER_HOST#$SERVER_HOST#g" /etc/apache2/sites-available/ssl.conf RUN a2enmod headers ssl proxy proxy_http rewrite && a2ensite ssl RUN echo "https://$CONTROLLER_URL" > /var/www/html/.professos  # Start the application and apache/nginx server COPY docker-entrypoint.sh ${SUBDIR}/ WORKDIR ${SUBDIR} ENTRYPOINT ["./docker-entrypoint.sh"]

From this point, it is possible to add two or more configured instances to the docker-compose.yml file. Every instance can be tested independently and without influencing each other. This independence enables us to test various switches, e.g., different flows or authentication methods in different combinations.

app1-implicit:     build:       context: rp/app1       args:         FLOW: "implicit"         CONTROLLER_URL: ${CONTROLLER_HOST}         CLIENT_HOST: ${APP1-IMPLICIT}     depends_on:       - certs     volumes:       - certs:/certs:ro     env_file:       - .proxy_env     environment:       CA_DIR: ${CA_DIR}       CA_CERT: ${CA_CERT}       VIRTUAL_HOST: ${APP1-IMPLICIT}     networks:       - rpnet       - profnet

app1-code:   build:     context: rp/app1     args:       FLOW: "code"           CONTROLLER_URL: ${CONTROLLER_HOST}       CLIENT_HOST: ${APP1-CODE}   depends_on:     - certs   volumes:     - certs:/certs:ro   env_file:     - .proxy_env   environment:     CA_DIR: ${CA_DIR}     CA_CERT: ${CA_CERT}     VIRTUAL_HOST: ${APP1-CODE}   networks:     - rpnet     - profnet

Client Side

The user solely has to establish a proxy connection to SERVERIP:8080. For example, in Firefox, the addon FoxyProxy can switch easily between different proxy settings.

It is advisable to install the generated Root-CA (oidc-ca.crt) in the browsers' certification store. Otherwise, self-signed certification warnings will be displayed. After the web browser is connected to the proxy, it should be possible to reach the landing page https://lab.

Automatic Tests with PrOfESSOS

We have two options for automatic tests with PrOfESSOS. We can either use the Web UI at https://professos, or call the RESTful API methods directly. Both options require a configuration file with target information. PrOfESSOS requires this information to find all needed URLs and parameter fields to login with selenium scripts.

You can use the following JSON file for the MITREid Connect Client:

{   "UrlClientTarget": "https://mitreid-client/simple-web-app/login",   "InputFieldName": "identifier",   "SeleniumScript": "",   "FinalValidUrl": "https://mitreid-client/simple-web-app/",   "HonestUserNeedle": "{sub=honest-op-test-subject, iss=https://honest-idp.professos/CHANGE_ME}",   "EvilUserNeedle": "{sub=evil-op-test-subject, iss=https://attack-idp.professos/CHANGE_ME}",   "ProfileUrl": "https://mitreid-client/simple-web-app/user" }

Only the CHANGE_ME parameter must be replaced manually with the displayed Test ID, as you can see in the following screenshot. The Test ID represents a unique OP address. This allows parallel testing as long as the implementation supports Dynamic Registration.

After clicking the "Learn" button, PrOfESSOS tries to log in with the honest and evil OP. Note that it takes a while until the process is finished.

If everything has worked as expected, PrOfESSOS displays a green checkmark. Otherwise, the UI provides minor logs and a few screenshots until the error has occurred. The MitMProxy Web UI can be a helpful additional tool to debug such issues.

On success, explicit tests or all tests can be executed. Each test step provides a small description and a test execution log.

The other option to start these tests is to use the RESTful API. Therefore, we provide a python cli tool in the oidc-docker-libs/oidc-lab-scripts folder. For all currently implemented RP and OP solutions, we have stored the json configurations. After starting the cli tool you solely need to select a target and run a complete test. An HTML report is also created which can be shared with collaborators.

#> ./cli.py [*] Professos CLI started Starting Control Center for Professos! cli> load rp mitreid-client  Start session default cli>> rp> mitreid-client> full_test Create new test plan: TestId = 6RZmcJHNd6o Learn: {     "HonestWebfingerResourceId": "https://honest-idp.professos/6RZmcJHNd6o",     "EvilWebfingerResourceId": "https://attack-idp.professos/6RZmcJHNd6o",     "UrlClientTarget": "https://mitreid-client/simple-web-app/login",     "InputFieldName": null,     "SeleniumScript": "",     "FinalValidUrl": "https://mitreid-client/simple-web-app",     "HonestUserNeedle": "{sub=honest-op-test-subject, iss=https://honest-idp.professos/6RZmcJHNd6o}",     "EvilUserNeedle": "{sub=evil-op-test-subject, iss=https://attack-idp.professos/6RZmcJHNd6o}",     "ProfileUrl": "https://mitreid-client/simple-web-app/user",     "Type": "de.rub.nds.oidc.test_model.TestRPConfigType" } ================================================================================ Run Test Step [0]: ID Spoofing 1 - ID Token (sub) - PASS ================================================================================ Run Test Step [1]: ID Spoofing 2 - ID Token (sub+iss) - PASS ================================================================================

Semi-Automated and Manual Tests

The MitMProxy can intercept and manipulate front and backend communication for minor manual tests. For example, the MITREid Connect client can perform user authentication with Keycloak as the OpenID provider. To simulate a redirect URI attack, you can intercept the Authentication Request or Token Request and manipulate the values.

Another reproducible way is to combine a specific PrOfESSOS attack, and a prepared script that is uploaded to the MitM scripting interface. Therefore, we added a server application to the MitM scripting interface, which can be controlled with the lab script cli tool.

We used such a workflow to check if a special redirect URI is vulnerable to an XSS attack. You can try it on your own. The command to prepare this attack is:

./cli.py [*] Professos CLI started Starting Control Center for Professos! cli> load op mitreid-server  Start session default cli>> op> mitreid-server> create Create new test plan: TestId = vWmdL4XHe2w cli>> op> mitreid-server> learn Learn: {     "HonestRpResourceId": "https://rp.professos/vWmdL4XHe2w",     "EvilRpResourceId": "https://evilrp.professos/vWmdL4XHe2w",     "UrlOPTarget": "https://mitreid-server/oidc-server",     "OPMetadata": "",     "AccessToken1": "",     "AccessToken2": "",     "User1Name": "user1",     "User2Name": "user2",     "User1Pass": "user1pass",     "User2Pass": "user2pass",     "LoginScript": "",     "ConsentScript": "",     "Client1Config": "",     "Client2Config": "",     "Type": "de.rub.nds.oidc.test_model.TestOPConfigType" } cli>> op> mitreid-server> run_pyscript pentest/mitreid-server-redirect.py Received: OK Received: OK cli>> op> mitreid-server> run 48 ================================================================================ Run Test Step [48]: Custom 1 - Redirect URI - PASS cli>> op> mitreid-server> export cli>> op> mitreid-server> report

As a result, in the screenshot you can see that our javascript was escaped correctly.

Another new feature for RP tests is to expose a specific attack pattern with PrOfESSOS and go through the login process manually with a browser. This is archived with the cli and the expose command. If you want to test, execute these commands:

./cli.py [*] Professos CLI started Starting Control Center for Professos! cli> load rp mitreid-client  Start session default cli>> rp> mitreid-client> create Create new test plan: TestId = hDOAisJy9OE cli>> rp> mitreid-client> learn Learn: {     "HonestWebfingerResourceId": "https://honest-idp.professos/hDOAisJy9OE",     "EvilWebfingerResourceId": "https://attack-idp.professos/hDOAisJy9OE",     "UrlClientTarget": "https://mitreid-client/simple-web-app/login",     "InputFieldName": null,     "SeleniumScript": "",     "FinalValidUrl": "https://mitreid-client/simple-web-app",     "HonestUserNeedle": "{sub=honest-op-test-subject, iss=https://honest-idp.professos/hDOAisJy9OE}",     "EvilUserNeedle": "{sub=evil-op-test-subject, iss=https://attack-idp.professos/hDOAisJy9OE}",     "ProfileUrl": "https://mitreid-client/simple-web-app/user",     "Type": "de.rub.nds.oidc.test_model.TestRPConfigType" } cli>> rp> mitreid-client> expose --test 3

Start login at https://mitreid-client/simple-web-app/login
For the OpenID Provider use the exposed attacker OP address https://attack-idp.professos/CHANGE_ME which can be copied from the learn step.
The browser should display a simple message: Authentication Failed: Id Token Issuer is null -> Our attack was unsuccessful
The honest OP address can be used to compare the result with a successful login attempt.

References

Acknowledgement

The master's thesis was supervised by Vladislav Mladenov, Christian Mainka, and Jörg Schwenk. Thank you for the support and opportunity to write this thesis.

Author of this Post

Christian Fries

Name	Vulnerability	Fixed	CVE
MITREid Connect	PKCE Downgrade Attack	✦
mod auth openidc	ID Spoofing, JWKS Spoofing	✔
node oidc-provider	Redirect URI Manipulation	✖
OidcRP	Replay Attack	✦
phpOIDC	Message Flow Confusion, ID Spoofing, Key Confusion	✦
pyoidc	Replay Attack, Signature Manipulation, Token Recipient Confusion	✔	CVE-2020-26244

Prabhu's Maya

Tuesday, May 30, 2023

Security And Privacy Of Social Logins (III): Privacy In Single Sign-On Protocols

Overview

Part I: Single Sign-On Protocols in the Wild

Part II: PostMessage Security in Single Sign-On

Part III: Privacy in Single Sign-On Protocols

Introduction to XS-Leaks in Single Sign-On

XS-Leaks in Single Sign-On: Account Leakage Attack

XS-Leaks in Single Sign-On: Identity Leakage Attack

Acknowledgments

Authors of this Post

Related articles

Security Analysis In An OpenID Connect Lab Environment

Introduction

PrOfESSOS

Supported attacks on Relying Parties

Supported attacks on OpenID Provider

The Lab Environment

Overview

Setup

Server Side

Docker Structure

Client Side

Automatic Tests with PrOfESSOS

Semi-Automated and Manual Tests

References

Acknowledgement

Author of this Post

More info

Blog Archive

About Me

Prabhu's Maya

Tuesday, May 30, 2023

Security And Privacy Of Social Logins (III): Privacy In Single Sign-On Protocols

Overview

Part I: Single Sign-On Protocols in the Wild

Part II: PostMessage Security in Single Sign-On

Part III: Privacy in Single Sign-On Protocols

Introduction to XS-Leaks in Single Sign-On

XS-Leaks in Single Sign-On: Account Leakage Attack

XS-Leaks in Single Sign-On: Identity Leakage Attack

Automatic Sign-In and Session Management Practices in the Wild

Acknowledgments

Authors of this Post

Related articles

Security Analysis In An OpenID Connect Lab Environment

Introduction

PrOfESSOS

Supported attacks on Relying Parties

Supported attacks on OpenID Provider

The Lab Environment

Overview

Setup

Server Side

Docker Structure

Client Side

Automatic Tests with PrOfESSOS

Semi-Automated and Manual Tests

References

Acknowledgement

Author of this Post

More info

Blog Archive

About Me