Self-XSS (self cross-site scripting) is a social engineering attack used to gain control of victims' web accounts. In a Self-XSS attack, the victim of the attack unknowingly runs malicious code in their own web browser, thus exposing personal information to the attacker, a kind of vulnerability known as cross-site scripting. [1]
Self-XSS operates by tricking users also into copying and pasting malicious content into their browsers' web developer console. [1] Usually, the attacker posts a message that says by copying and running certain code, the user will be able to receive virtual rewards or hack a website. In fact, the code allows the attacker to hijack the victim's account. [2]
In the past, a very similar attack took place, in which users were tricked into pasting malicious JavaScript into their address bar. When browser vendors stopped this by preventing easily running JavaScript from the address bar, [3] [4] Attackers started using Self-XSS in its current form. Web browser vendors and web sites have taken steps to mitigate this attack. Firefox [5] and Google Chrome [6] have both begun implementing safeguards to warn users about Self-XSS attacks. Facebook and others now display a warning message when users open the web developer console, and they link to pages explaining the attack in detail. [7] [8]
The "self" part of the name comes from the fact that the user is attacking themselves. The "XSS" part of the name comes from the abbreviation for cross-site scripting, because both attacks result in malicious code running on a legitimate site. However, the attacks do not have much else in common, because XSS is an attack against the website itself (which users cannot protect themselves against but can be fixed by the site operator making their site more secure), whereas Self-XSS is a social engineering attack against the user (against which savvy users can protect themselves but the site operator cannot prevent). [9]
JavaScript, often abbreviated as JS, is a programming language and core technology of the World Wide Web, alongside HTML and CSS. As of 2024, 98.9% of websites use JavaScript on the client side for webpage behavior, often incorporating third-party libraries. All major web browsers have a dedicated JavaScript engine to execute the code on users' devices.
A bookmarklet is a bookmark stored in a web browser that contains JavaScript commands that add new features to the browser. They are stored as the URL of a bookmark in a web browser or as a hyperlink on a web page. Bookmarklets are usually small snippets of JavaScript executed when user clicks on them. When clicked, bookmarklets can perform a wide variety of operations, such as running a search query from selected text or extracting data from a table.
Cross-site scripting (XSS) is a type of security vulnerability that can be found in some web applications. XSS attacks enable attackers to inject client-side scripts into web pages viewed by other users. A cross-site scripting vulnerability may be used by attackers to bypass access controls such as the same-origin policy. During the second half of 2007, XSSed documented 11,253 site-specific cross-site vulnerabilities, compared to 2,134 "traditional" vulnerabilities documented by Symantec. XSS effects vary in range from petty nuisance to significant security risk, depending on the sensitivity of the data handled by the vulnerable site and the nature of any security mitigation implemented by the site's owner network.
Phishing is a form of social engineering and scam where attackers deceive people into revealing sensitive information or installing malware such as ransomware. Phishing attacks have become increasingly sophisticated and often transparently mirror the site being targeted, allowing the attacker to observe everything while the victim is navigating the site, and transverse any additional security boundaries with the victim. As of 2020, it is the most common type of cybercrime, with the FBI's Internet Crime Complaint Center reporting more incidents of phishing than any other type of computer crime.
In computing, Download.ject is a malware program for Microsoft Windows servers. When installed on an insecure website running on Microsoft Internet Information Services (IIS), it appends malicious JavaScript to all pages served by the site.
Code injection is the exploitation of a computer bug that is caused by processing invalid data. The injection is used by an attacker to introduce code into a vulnerable computer program and change the course of execution. The result of successful code injection can be disastrous, for example, by allowing computer viruses or computer worms to propagate.
A spoofed URL involves one website masquerading as another, often leveraging vulnerabilities in web browser technology to facilitate a malicious computer attack. These attacks are particularly effective against computers that lack up-to- security patches. Alternatively, some spoofed URLs are crafted for satirical purposes.
Cross-zone scripting is a browser exploit taking advantage of a vulnerability within a zone-based security solution. The attack allows content (scripts) in unprivileged zones to be executed with the permissions of a privileged zone - i.e. a privilege escalation within the client executing the script. The vulnerability could be:
NoScript is a free and open-source extension for Firefox- and Chromium-based web browsers, written and maintained by Giorgio Maone, a software developer and member of the Mozilla Security Group.
HTTP cookies are small blocks of data created by a web server while a user is browsing a website and placed on the user's computer or other device by the user's web browser. Cookies are placed on the device used to access a website, and more than one cookie may be placed on a user's device during a session.
JSONP, or JSON-P, is a historical JavaScript technique for requesting data by loading a <script> element, which is an element intended to load ordinary JavaScript. It was proposed by Bob Ippolito in 2005. JSONP enables sharing of data bypassing same-origin policy, which disallows running JavaScript code to read media DOM elements or XMLHttpRequest data fetched from outside the page's originating site. The originating site is indicated by a combination of URI scheme, hostname, and port number.
An XSS worm, sometimes referred to as a cross site scripting virus, is a malicious payload, usually written in JavaScript, that breaches browser security to propagate among visitors of a website in the attempt to progressively infect other visitors. They were first mentioned in 2002 in relation to a cross site scripting vulnerability in Hotmail.
Clickjacking is a malicious technique of tricking a user into clicking on something different from what the user perceives, thus potentially revealing confidential information or allowing others to take control of their computer while clicking on seemingly innocuous objects, including web pages.
Malvertising is the use of online advertising to spread malware. It typically involves injecting malicious or malware-laden advertisements into legitimate online advertising networks and webpages. Because advertising content can be inserted into high-profile and reputable websites, malvertising provides malefactors an opportunity to push their attacks to web users who might not otherwise see the ads, due to firewalls, more safety precautions, or the like. Malvertising is "attractive to attackers because they 'can be easily spread across a large number of legitimate websites without directly compromising those websites'."
Cross-site request forgery, also known as one-click attack or session riding and abbreviated as CSRF or XSRF, is a type of malicious exploit of a website or web application where unauthorized commands are submitted from a user that the web application trusts. There are many ways in which a malicious website can transmit such commands; specially-crafted image tags, hidden forms, and JavaScript fetch or XMLHttpRequests, for example, can all work without the user's interaction or even knowledge. Unlike cross-site scripting (XSS), which exploits the trust a user has for a particular site, CSRF exploits the trust that a site has in a user's browser. In a CSRF attack, an innocent end user is tricked by an attacker into submitting a web request that they did not intend. This may cause actions to be performed on the website that can include inadvertent client or server data leakage, change of session state, or manipulation of an end user's account.
Content Security Policy (CSP) is a computer security standard introduced to prevent cross-site scripting (XSS), clickjacking and other code injection attacks resulting from execution of malicious content in the trusted web page context. It is a Candidate Recommendation of the W3C working group on Web Application Security, widely supported by modern web browsers. CSP provides a standard method for website owners to declare approved origins of content that browsers should be allowed to load on that website—covered types are JavaScript, CSS, HTML frames, web workers, fonts, images, embeddable objects such as Java applets, ActiveX, audio and video files, and other HTML5 features.
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Browser security is the application of Internet security to web browsers in order to protect networked data and computer systems from breaches of privacy or malware. Security exploits of browsers often use JavaScript, sometimes with cross-site scripting (XSS) with a secondary payload using Adobe Flash. Security exploits can also take advantage of vulnerabilities that are commonly exploited in all browsers.
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History sniffing is a class of web vulnerabilities and attacks that allow a website to track a user's web browsing history activities by recording which websites a user has visited and which the user has not. This is done by leveraging long-standing information leakage issues inherent to the design of the web platform, one of the most well-known of which includes detecting CSS attribute changes in links that the user has already visited.