Websites, web apps, and web services have become vital for how most businesses operate today. However, with this reliance comes substantial security risks that too often go overlooked.
attackers actively scan for and exploit common web application vulnerabilities to breach networks, steal data, commit fraud, and hijack infrastructure for their own ends. Staying on top of the most dangerous web app threats is key for protecting your organization in the modern threat landscape.
In this comprehensive guide, you’ll learn about the top application security threats identified by industry experts and standards bodies like OWASP. You’ll also get recommendations tailored to your business on guarding against attacks and minimizing your exposure. With vigilance and focus in applying security best practices, you can develop a robust application security postures.
An Overview of the Top 9 Web Application Security Threats
Recent research from RiskBased Security revealed a record-setting 3,832 reported breaches exposing over 4.5 billion records in the first 6 months of 2022 alone. Web application attacks play a central role in these incidents.
The following 9 threats have consistently ranked among the most widespread and devastating web app vulnerability categories:
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Injection Attacks – Inserting interpreting user input as insecure code leading to eCRM theft, data destruction, DoS
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Broken Authentication – Flawed auth checks allowing account takeover, privilege escalation
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Sensitive Data Exposure – Unencrypted assets allowing attackers to easily intercept and exfiltrate sensitive data
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XML External Entities (XXE) – Poorly configured XML processors expose documents and allow server side request forgery
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Broken Access Control – Restriction misconfigurations enable unauthorized data access, moderator privilege escalation
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Security Misconfiguration – Failure to secure components and servers allow for easy unauthorized access
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Cross-Site Scripting (XSS) – Injecting malicious scripts into web pages to access accounts, steal data, or deface sites
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Insecure Deserialization – Serialized objects enable remote code execution on affected servers
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Using Components with Known Vulnerabilities – Well-understood exploits targeting outdated frameworks, libraries, components expand attack surface
These nine threats accounted for over 75% of real-world web application breaches over the past 10 years. Attackers continue finding new ways to exploit them.
Understanding specifics on how these attacks work and the business impact they incur is crucial for prioritizing your defenses.
Web Application Security Threat #1: Injection Attacks
Injection attacks exploit user input fields, APIs, or data stores to “inject” malicious payloads and commands into web apps. They trick apps into executing dangerous functions they weren’t designed to handle.
Example injection attack scenarios include:
- Embedding malicious SQL database queries – Reading/modifying sensitive records, destroying data
- Injecting OS commands – Deleting files, installing backdoors
- Sending forged API requests – Executing account takeovers, fraudulent transactions
Verizon’s 2022 breach report revealed that injection attacks make up 31% of all breaches investigated. They are among the quickest, easiest threats for hackers to exploit.
A single web form vulnerable to SQL injection would have enabled attackers to steal 3.7 million payment records from UK airline group EasyJet in 2020. Remediating the flaw after its discovery took over 2 months.
Prevention requires validating and sanitizing any user inputs. Constraints must be applied on length, format, and characters to deny potentially malicious values.
Recommendation
Scrutinize user inputs and utilize stringent allow/deny lists covering special syntax and characters. Encode data prior to interpreting it as SQL queries or system commands.
Web Application Security Threat #2: Broken Authentication
Attackers are targeting account credentials more than ever before through phishing campaigns and brute force credential stuffing. However, modern authentication systems incorporate safeguards to deter unauthorized logins even in the event of stolen credentials.
When these systems suffer flaws, account hijacking and privilege escalation become trivial:
- Weak password policies facilitate brute forcing
- Unencrypted password storage enables retrieval
- Session management flaws allow session reuse/hijacking
- Failing account lockouts permit unlimited guessing
Attackers logged into accounts can operate freely, siphoning data, manipulating records, and moving laterally within corporate networks.
The 2022 Verizon DBIR found over 20% of breaches involved brute force or the use of lost or stolen credentials.
Uber concealed a 2016 breach of 57 million user accounts resulting from their own flawed infrastructure. Roughly $148 million was reportedly paid to the attackers.
This catastrophic scenario can be prevented by following password policy best practices and modern authentication protocols built on encryption, ephemeral tokens, strict session management, and account lockouts.
Recommendation
Enforce automatic session termination following user actions like logout or periods of inactivity. Additionally, require strong password policies and utilize multi-factor authentication with short-lived, encrypted tokens.
Web Application Security Threat #3: Sensitive Data Exposure
The most sought-after bounty for web-based attacks is proprietary information like customer data or trade secrets. When web apps fail to protect sensitive assets through encryption and access controls, gaining this data becomes effortless.
- Unencrypted data gets intercepted through insecure connections or improper error handling messages.
- Weak access policies permit unauthorized views of repositories housing sensitive documents.
- Auditing & activity monitoring measures fail to detect abnormally high data access and transfers.
Attackers siphoning this data sell it online or utilize it themselves for insider trading, identity theft, and targeted social engineering campaigns directed internally.
A 2022 Imperva report analyzing 20,000+ applications found:
- 44% lacked complete encryption on login and registration pages transmitting credentials.
- 39% enabled search indexing of sensitive pages leaking data publicly.
- 58% contained legacy HTTP references leaking data when interacting with HTTP resources.
Safeguarding proprietary data requires utilizing mechanisms like data categorization, classification, and tagging in conjunction with compartmentalized access controls, encryption, activity monitoring, and database audit logging.
Recommendation
Enforce encryption in transit and at rest for assets like credentials, payment data, personal information, secrets, code, keys and build mandatory data security governance into development processes.
Web Application Security Threat #4: XML External Entities (XXE) Injection
Exploitation of XML external entities often allows attackers to interact with unauthorized OS files and connected services from vulnerable XML processing applications.
Though less pervasive than other web app threats, consequences of XXE attacks include denial of service, server side request forgery, port scanning, file retrieval, privileged information disclosure, and system instability.
The root cause lies in outdated or poorly configured XML parsers evaluating external entity references within XML documents. By manipulating submitted data, an attacker can exploit the parser and breathaches.
Successful XXE attacks are rare but damaging. In 2017, financial services provider S&P Global fell victim to an XXE vulnerability subsequently leveraged to orchestrate unauthorized wires transfers totaling $1.75 million. The flaw originated from an overlooked XML parser enabled on a web server exposed to partners for file uploading.
Fortifying XML handling requires categorically denying DTD and entity processing while implementing positive validation of all inputs, data formats, and serialization.
Recommendation
Categorically deny all XML document type definitions for user input while restricting permitted entity types and whitelisting partner upload file types. Actively patch and upgrade vulnerable frameworks containing XML processing engines.
Web Application Security Threat #5: Broken Access Controls
Access controls regulate what data and functionality is available to both standard and privileged web app users. Bypassing these restrictions undermines security and enables numerous illicit activities.
Flawed access checks frequently permit actions like:
- Accessing other user accounts containing sensitive information
- Viewing pages and assets only visible to senior leadership
- Invoking admin functions ordinary users lack permissions for
- Utilizing unauthorized API endpoints only meant for backend services
These lapses subsequently enable fraud, espionage, vandalism and privilege escalation.
A 2021 breach affecting 40 million user accounts of popular password manager LastPass occurred using an anonymous account with no special access. Nonetheless, the threat actor successfully abused broken access control checks to elevate privilege before achieving complete system compromise.
Codifying and implementing least privilege and separation of duties backed by automated, centralized access policies closes off misconfigurations attackers actively probe for.
Recommendation
Incorporate context-aware access controls using attributes like user roles, trusted IPs, and acceptable device types in addition to enforcing compartmentalization of job functions.
Web Application Security Threat #6: Security Misconfigurations
Web applications rely upon layers of interconnected platform components, services, servers, databases, APIs, libraries, and more which require ongoing security hardening and updates.
In practice, misconfigurations here enable some of the easiest, most devastating initial access:
- Unnecessary ports/services left running on servers
- Unpatched vulnerabilities in frameworks/dependencies
- Overly permissive file/folder permissions
- Exposed cloud storage instances, debugging interfaces
- Hardcoded/duplicate credentials across environments
- Verbose error messaging disclosing architecture
With so much to validate, gaps inevitably occur over time as components update and evolve. Attentive attackers probe for any infrastructure or software exhibiting versioning, missing patches, unsafe defaults or deprecated capabilities.
These footholds then facilitate injection attacks, backdoors, traffic sniffing, and lateral traversal towards higher value targets across internal networks.
A 2022 study by Piper Sandler found 26% of developer teams knowingly ship software containing over 100 sever security misconfigurations due to pressures like release deadlines.
Establishing continuously running, automated security pipelines catching and addressing errors pre-production radically reduces exploitation potential.
Recommendation
Implement rigid configuration management upholding secure baselines coupled with extensive pre-production scanning of infrastructure, dependencies, permissions, exposures and credentials. Remediate all medium+ severity flaws prior to release.
Web Application Security Threat #7: Cross-Site Scripting XSS
Cross site scripting works by embedding malicious code like JavaScript into web pages and apps to bypass access controls and extract sensitive browser-based data.
Common XSS attack goals include:
- Stealing or manipulating user cookies containing session data
- Capturing user keystrokes to grab credentials directly
- Hijacking user accounts by rewriting entire pages
- Redirect users to phishing sites imitating legitimate domains
- Using browsers as launch points for further malware installation
Perpetrators often find XSS flaws in web apps allowing input fields, comments or URLs to go unvalidated. Attackers then prepare malicious links or inputs to feed vulnerable parameters.
When victims click crafted links or submit altered input, the injected scripts execute inside the user’s browser secured by that user’s permissions on the vulnerable site. This leads to user account compromise and session hijacking.
Research shows at least 70% of web apps contain some XSS vulnerabilities, with around 65k unique flaws discovered annually. Over 25% remain unpatched after a year allowing prolonged exploitation.
Robust input validation blocks unintentional code execution early on, whereas constant patching limits findable flaws.
Recommendation
Validate and sanitize all user supplied web app inputs. Encode or transform data prior to outputting pages to prevent embedded scripts from interpreting user generated content as code.
Web Application Security Threat #8: Insecure Deserialization
Insecure deserialization flaws in web apps enable serious attack scenarios including denial of service, memory exhaustion, SQL injection, remote code execution and more.
The underlying factors enabling these exploits are:
- Serialized objects encoded from untrusted sources
- Dangerous methods invoked during deserialization
- Classes accessible in the app’s environment with harmful side effects
Though patching prevents known vulnerable component abuse, completely eradicating serialization issues requires robust input validation and business logic checks on deserialized data flowing into high privileged functions.
Real world examples showcase the immense damage possible via these relatively uncommon but devastating bugs:
- A 2020 PayPal vulnerability permitted remote code execution by injecting additional fields in cookies undergoing insecure serialization.
- Similar flaws discovered in authentication functionality for popular Ruby libraries in 2021 enabled execution of commands sent over the network.
- 2022 reports revealed four major US pharmacy chains had a Java serialization issue allowing access to internal networks.
As web apps continue relying on powerful serialization formats for marshaling and storing structured data, extra controls must safeguard these pathways from abuse.
Recommendation
When utilizing serialization, ensure only trusted sources provide inputs. Validate, sanitize and type check deserialized data before consumption while denying functionality invoking unsafe system-level changes.
Web Application Security Threat #9: Known Vulnerable Components
Today‘s web applications intrinsically depend on integrated third party elements like libraries, frameworks and modules to enable rapid deployment.
Unfortunately, this mass interconnection also transfers vulnerability risks:
- Near infinite combinations of layered components
- Frequent releases and revisions of each dependency
- Lacking visibility into full inventory of in-use components
- Proof of concept exploits quickly adapted for new flaws
Rather than attacking hardened web apps directly, hackers target whichever interconnected element exhibits the weakest security posture.
Single vulnerable libraries contained across thousands of web apps then enable hugely widespread compromise. This recently occurred with the Log4j logging library vulnerability enabling remote code execution via log messages.
Vigilantly tracking and addressing third party vulnerabilities is crucial but operationally challenging with modern dynamic architectures.
Prioritizing components handling sensitive data or elevated privileges limits the blast radius from any future disclosures. Enforcing system integrity monitoring also quickly exposes malicious modifications stemming from exploited libraries.
Recommendation
Continuously monitor advisories related to integrated software components and frameworks. Place focus on patching components handling authentication, session management, data access APIs, cryptography functions and transmission of sensitive assets.
Steps You Must Take to Secure Web Applications
With web apps representing prime targets and data breaches carrying immense financial penalties, applying security fundamentals is a must. Prioritize actions securing against the most prolific threats listed here when allocating resources:
Utilize Robust Input Validation
Scrutinizing and sanitizing all externally supplied input defends against devastating injection attacks compromising confidentiality, integrity and availability.
Employ Strict Access Controls
Compartmentalizing access through granular privilege segmentation, attribute based access control and redundancy limiting designs prevents abuse of misconfigurations.
Routinely Test Authentication
Rigorously pen testing identity and access management controls using automated vulnerability scanners and credential stuffing tools ensures account security barriers remain intact.
Encrypt Sensitive Communications
Consistently encrypting transmitted data and seeking data minimization opportunities removes easy surveillance and theft opportunities.
Establish AppSec Testing Pipeline
Static scans (SAST), dynamic scans (DAST) and interactive analysis (IAST) injected throughout development uncover flaws early on when easier to address.
Inventory/Update External Components
Maintaining real-time visibility into integrated third party plugin versions and licensing terms paired with rapid patching audits reduces exploitability.
Subscribe to Vulnerability Feeds
Tuning into comprehensive vulnerability and threat intelligence sources focused on libraries and dependencies denies attackers the upper hand provided by undisclosed exploits circulating amongst underground communities.
Schedule Penetration Tests
Consulting seasoned security professionals to legally attack your web apps using cutting edge techniques reveals previously unknown attack vectors needing safeguards.
The threats show no signs of slowing. But taking these steps makes devastating application layer breaches far less likely. Provide your organization the advantage of a hardened security posture in the face of continuous attacks.
