• / [uid cookie]
• /index.php [uid cookie]
• /index.php [username parameter]
• /index.php [username parameter]

SQL injection vulnerabilities arise when user-controllable data is incorporated into database SQL queries in an unsafe manner. An attacker can supply crafted input to break out of the data context in which their input appears and interfere with the structure of the surrounding query.

A wide range of damaging attacks can often be delivered via SQL injection, including reading or modifying critical application data, interfering with application logic, escalating privileges within the database and taking control of the database server.

The most effective way to prevent SQL injection attacks is to use parameterized queries (also known as prepared statements) for all database access. This method uses two steps to incorporate potentially tainted data into SQL queries: first, the application specifies the structure of the query, leaving placeholders for each item of user input; second, the application specifies the contents of each placeholder. Because the structure of the query has already been defined in the first step, it is not possible for malformed data in the second step to interfere with the query structure. You should review the documentation for your database and application platform to determine the appropriate APIs which you can use to perform parameterized queries. It is strongly recommended that you parameterize every variable data item that is incorporated into database queries, even if it is not obviously tainted, to prevent oversights occurring and avoid vulnerabilities being introduced by changes elsewhere within the code base of the application.

You should be aware that some commonly employed and recommended mitigations for SQL injection vulnerabilities are not always effective:

• One common defense is to double up any single quotation marks appearing within user input before incorporating that input into a SQL query. This defense is designed to prevent malformed data from terminating the string into which it is inserted. However, if the data being incorporated into queries is numeric, then the defense may fail, because numeric data may not be encapsulated within quotes, in which case only a space is required to break out of the data context and interfere with the query. Further, in second-order SQL injection attacks, data that has been safely escaped when initially inserted into the database is subsequently read from the database and then passed back to it again. Quotation marks that have been doubled up initially will return to their original form when the data is reused, allowing the defense to be bypassed.
• Another often cited defense is to use stored procedures for database access. While stored procedures can provide security benefits, they are not guaranteed to prevent SQL injection attacks. The same kinds of vulnerabilities that arise within standard dynamic SQL queries can arise if any SQL is dynamically constructed within stored procedures. Further, even if the procedure is sound, SQL injection can arise if the procedure is invoked in an unsafe manner using user-controllable data.

• Web Security Academy: SQL injection
• Using Burp to Test for Injection Flaws
• Web Security Academy: SQL Injection Cheat Sheet

• CWE-89: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
• CWE-94: Improper Control of Generation of Code ('Code Injection')
• CWE-116: Improper Encoding or Escaping of Output
• CAPEC-66: SQL Injection

File path traversal vulnerabilities arise when user-controllable data is used within a filesystem operation in an unsafe manner. Typically, a user-supplied filename is appended to a directory prefix in order to read or write the contents of a file. If vulnerable, an attacker can supply path traversal sequences (using dot-dot-slash characters) to break out of the intended directory and read or write files elsewhere on the filesystem.

This is typically a very serious vulnerability, enabling an attacker to access sensitive files containing configuration data, passwords, database records, log data, source code, and program scripts and binaries.

Ideally, application functionality should be designed in such a way that user-controllable data does not need to be passed to filesystem operations. This can normally be achieved by referencing known files via an index number rather than their name, and using application-generated filenames to save user-supplied file content.

If it is considered unavoidable to pass user-controllable data to a filesystem operation, three layers of defense can be employed to prevent path traversal attacks:

• User-controllable data should be strictly validated before being passed to any filesystem operation. In particular, input containing dot-dot sequences should be blocked.
• After validating user input, the application can use a suitable filesystem API to verify that the file to be accessed is actually located within the base directory used by the application. In Java, this can be achieved by instantiating a java.io.File object using the user-supplied filename and then calling the getCanonicalPath method on this object. If the string returned by this method does not begin with the name of the start directory, then the user has somehow bypassed the application's input filters, and the request should be rejected. In ASP.NET, the same check can be performed by passing the user-supplied filename to the System.Io.Path.GetFullPath method and checking the returned string in the same way as described for Java.
• The directory used to store files that are accessed using user-controllable data can be located on a separate logical volume to other sensitive application and operating system files, so that these cannot be reached via path traversal attacks. In Unix-based systems, this can be achieved using a chrooted filesystem; on Windows, this can be achieved by mounting the base directory as a new logical drive and using the associated drive letter to access its contents.

• Web Security Academy: Directory traversal

• CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
• CWE-23: Relative Path Traversal
• CWE-35: Path Traversal: '.../...//'
• CWE-36: Absolute Path Traversal
• CAPEC-126: Path Traversal

• /index.php [User-Agent HTTP header]
• /index.php [do parameter]
• /index.php [showhints cookie]
• /index.php [uid cookie]
• /index.php [username cookie]

XPath injection vulnerabilities arise when user-controllable data is incorporated into XPath queries in an unsafe manner. An attacker can supply crafted input to break out of the data context in which their input appears and interfere with the structure of the surrounding query.

Depending on the purpose for which the vulnerable query is being used, an attacker may be able to exploit an XPath injection flaw to read sensitive application data or interfere with application logic.

User input should be strictly validated before being incorporated into XPath queries. In most cases, it will be appropriate to accept input containing only short alphanumeric strings. At the very least, input containing any XPath metacharacters such as " ' / @ = * [ ] ( and ) should be rejected.

• Web Security Academy: Client-side XPath injection (DOM-based)

• CWE-94: Improper Control of Generation of Code ('Code Injection')
• CWE-116: Improper Encoding or Escaping of Output
• CWE-159: Failure to Sanitize Special Element
• CWE-643: Improper Neutralization of Data within XPath Expressions ('XPath Injection')
• CAPEC-83: XPath Injection

Out-of-band resource load arises when it is possible to induce an application to fetch content from an arbitrary external location, and incorporate that content into the application's own response(s). The ability to trigger arbitrary out-of-band resource load does not constitute a vulnerability in its own right, and in some cases might even be the intended behavior of the application. However, in many cases, it can indicate a vulnerability with serious consequences.

The ability to request and retrieve web content from other systems can allow the application server to be used as a two-way attack proxy. By submitting suitable payloads, an attacker can cause the application server to attack, or retrieve content from, other systems that it can interact with. This may include public third-party systems, internal systems within the same organization, or services available on the local loopback adapter of the application server itself. Depending on the network architecture, this may expose highly vulnerable internal services that are not otherwise accessible to external attackers.

Additionally, the application's processing of web content that is retrieved from arbitrary URLs exposes some important and non-conventional attack surface. An attacker can deploy a web server that returns malicious content, and then induce the application to retrieve and process that content. This processing might give rise to the types of input-based vulnerabilities that are normally found when unexpected input is submitted directly in requests to the application. The out-of-band attack surface that the application exposes should be thoroughly tested for these types of vulnerabilities.

You should review the purpose and intended use of the relevant application functionality, and determine whether the ability to trigger arbitrary out-of-band resource load is intended behavior. If so, you should be aware of the types of attacks that can be performed via this behavior and take appropriate measures. These measures might include blocking network access from the application server to other internal systems, and hardening the application server itself to remove any services available on the local loopback adapter. You should also ensure that content retrieved from other systems is processed in a safe manner, with the usual precautions that are applicable when processing input from direct incoming web requests.

If the ability to trigger arbitrary out-of-band resource load is not intended behavior, then you should implement a whitelist of permitted URLs, and block requests to URLs that do not appear on this whitelist.

• Burp Collaborator
• Out-of-band application security testing (OAST)
• PortSwigger Research: Cracking the Lens

• CWE-610: Externally Controlled Reference to a Resource in Another Sphere
• CWE-918: Server-Side Request Forgery (SSRF)

Client-side desync (CSD) vulnerabilities occur when a web server fails to correctly process the Content-Length of POST requests. By exploiting this behavior, an attacker can force a victim's browser to desynchronize its connection with the website, typically leading to XSS.

You can resolve this vulnerability by patching the server so that it either processes POST requests correctly, or closes the connection after handling them. You could also disable connection reuse entirely, but this may reduce performance. You can also resolve this issue by enabling HTTP/2.

• HTTP Request Smuggling
• Browser-Powered Desync Attacks

• CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')
• CAPEC-33: HTTP Request Smuggling

• /index.php [page parameter]
• /index.php [username parameter]
• / [User-Agent HTTP header]
• /index.php [User-Agent HTTP header]
• /set-up-database.php [Referer HTTP header]

Reflected cross-site scripting vulnerabilities arise when data is copied from a request and echoed into the application's immediate response in an unsafe way. An attacker can use the vulnerability to construct a request that, if issued by another application user, will cause JavaScript code supplied by the attacker to execute within the user's browser in the context of that user's session with the application.

The attacker-supplied code can perform a wide variety of actions, such as stealing the victim's session token or login credentials, performing arbitrary actions on the victim's behalf, and logging their keystrokes.

Users can be induced to issue the attacker's crafted request in various ways. For example, the attacker can send a victim a link containing a malicious URL in an email or instant message. They can submit the link to popular web sites that allow content authoring, for example in blog comments. And they can create an innocuous looking web site that causes anyone viewing it to make arbitrary cross-domain requests to the vulnerable application (using either the GET or the POST method).

The security impact of cross-site scripting vulnerabilities is dependent upon the nature of the vulnerable application, the kinds of data and functionality that it contains, and the other applications that belong to the same domain and organization. If the application is used only to display non-sensitive public content, with no authentication or access control functionality, then a cross-site scripting flaw may be considered low risk. However, if the same application resides on a domain that can access cookies for other more security-critical applications, then the vulnerability could be used to attack those other applications, and so may be considered high risk. Similarly, if the organization that owns the application is a likely target for phishing attacks, then the vulnerability could be leveraged to lend credibility to such attacks, by injecting Trojan functionality into the vulnerable application and exploiting users' trust in the organization in order to capture credentials for other applications that it owns. In many kinds of application, such as those providing online banking functionality, cross-site scripting should always be considered high risk.

In most situations where user-controllable data is copied into application responses, cross-site scripting attacks can be prevented using two layers of defenses:

• Input should be validated as strictly as possible on arrival, given the kind of content that it is expected to contain. For example, personal names should consist of alphabetical and a small range of typographical characters, and be relatively short; a year of birth should consist of exactly four numerals; email addresses should match a well-defined regular expression. Input which fails the validation should be rejected, not sanitized.
• User input should be HTML-encoded at any point where it is copied into application responses. All HTML metacharacters, including < > " ' and =, should be replaced with the corresponding HTML entities (&lt; &gt; etc).

In cases where the application's functionality allows users to author content using a restricted subset of HTML tags and attributes (for example, blog comments which allow limited formatting and linking), it is necessary to parse the supplied HTML to validate that it does not use any dangerous syntax; this is a non-trivial task.

• Web Security Academy: Cross-site scripting
• Web Security Academy: Reflected cross-site scripting
• Using Burp to Find XSS issues

• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
• CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
• CWE-116: Improper Encoding or Escaping of Output
• CWE-159: Failure to Sanitize Special Element
• CAPEC-591: Reflected XSS

• The server's certificate is not valid for the server's hostname.
• The server's certificate is not trusted.

TLS (or SSL) helps to protect the confidentiality and integrity of information in transit between the browser and server, and to provide authentication of the server's identity. To serve this purpose, the server must present an TLS certificate that is valid for the server's hostname, is issued by a trusted authority and is valid for the current date. If any one of these requirements is not met, TLS connections to the server will not provide the full protection for which TLS is designed.

It should be noted that various attacks exist against TLS in general, and in the context of HTTPS web connections in particular. It may be possible for a determined and suitably-positioned attacker to compromise TLS connections without user detection even when a valid TLS certificate is used.

• SSL/TLS Configuration Guide

• CWE-295: Improper Certificate Validation
• CWE-326: Inadequate Encryption Strength
• CWE-327: Use of a Broken or Risky Cryptographic Algorithm

• https://testapp.secsci-autopt/index.php?page=user-info.php

• password

Some applications use the GET method to submit passwords, which are transmitted within the query string of the requested URL. Sensitive information within URLs may be logged in various locations, including the user's browser, the web server, and any forward or reverse proxy servers between the two endpoints. URLs may also be displayed on-screen, bookmarked or emailed around by users. They may be disclosed to third parties via the Referer header when any off-site links are followed. Placing passwords into the URL increases the risk that they will be captured by an attacker.

Vulnerabilities that result in the disclosure of users' passwords can result in compromises that are extremely difficult to investigate due to obscured audit trails. Even if the application itself only handles non-sensitive information, exposing passwords puts users who have re-used their password elsewhere at risk.

All forms submitting passwords should use the POST method. To achieve this, applications should specify the method attribute of the FORM tag as method="POST". It may also be necessary to modify the corresponding server-side form handler to ensure that submitted passwords are properly retrieved from the message body, rather than the URL.

• CWE-598: Information Exposure Through Query Strings in GET Request
• CAPEC-37: Retrieve Embedded Sensitive Data

• https://testapp.secsci-autopt/index.php?page=user-info.php

• password

Most browsers have a facility to remember user credentials that are entered into HTML forms. This function can be configured by the user and also by applications that employ user credentials. If the function is enabled, then credentials entered by the user are stored on their local computer and retrieved by the browser on future visits to the same application.

The stored credentials can be captured by an attacker who gains control over the user's computer. Further, an attacker who finds a separate application vulnerability such as cross-site scripting may be able to exploit this to retrieve a user's browser-stored credentials.

To prevent browsers from storing credentials entered into HTML forms, include the attribute autocomplete="off" within the FORM tag (to protect all form fields) or within the relevant INPUT tags (to protect specific individual fields).

Please note that modern web browsers may ignore this directive. In spite of this there is a chance that not disabling autocomplete may cause problems obtaining PCI compliance.

• CWE-200: Information Exposure

The application fails to prevent users from connecting to it over unencrypted connections. An attacker able to modify a legitimate user's network traffic could bypass the application's use of SSL/TLS encryption, and use the application as a platform for attacks against its users. This attack is performed by rewriting HTTPS links as HTTP, so that if a targeted user follows a link to the site from an HTTP page, their browser never attempts to use an encrypted connection. The sslstrip tool automates this process.

To exploit this vulnerability, an attacker must be suitably positioned to intercept and modify the victim's network traffic.This scenario typically occurs when a client communicates with the server over an insecure connection such as public Wi-Fi, or a corporate or home network that is shared with a compromised computer. Common defenses such as switched networks are not sufficient to prevent this. An attacker situated in the user's ISP or the application's hosting infrastructure could also perform this attack. Note that an advanced adversary could potentially target any connection made over the Internet's core infrastructure.

The application should instruct web browsers to only access the application using HTTPS. To do this, enable HTTP Strict Transport Security (HSTS) by adding a response header with the name 'Strict-Transport-Security' and the value 'max-age=expireTime', where expireTime is the time in seconds that browsers should remember that the site should only be accessed using HTTPS. Consider adding the 'includeSubDomains' flag if appropriate.

Note that because HSTS is a "trust on first use" (TOFU) protocol, a user who has never accessed the application will never have seen the HSTS header, and will therefore still be vulnerable to SSL stripping attacks. To mitigate this risk, you can optionally add the 'preload' flag to the HSTS header, and submit the domain for review by browser vendors.

• HTTP Strict Transport Security
• sslstrip
• HSTS Preload Form

• CWE-523: Unprotected Transport of Credentials
• CAPEC-94: Man in the Middle Attack
• CAPEC-157: Sniffing Attacks