On September 22, 2024, the CISA and FBI issued a joint advisory exposing active exploitation of Ivanti Cloud Service Appliances (CSA). What made this attack alarming was not a single severe vulnerability; it was a calculated chain of moderate vulnerabilities.
The attackers began with CVE-2024-8963, an admin bypass, followed by CVE-2024-9379, a SQL injection flaw to steal credentials. They completed the attack using CVE-2024-8190 and CVE-2024-9380 for remote code execution and Web shell persistence.
This was not a one-off exploit. It was a strategic sequence that led to full network compromise, proving that even low-severity bugs can be dangerous when combined.
In this blog, we will break down how these chains work, explore real-world examples, and share ways to detect and stop them before they escalate.
What Are Chained Vulnerabilities?
A chained vulnerability is a sequence of multiple vulnerabilities exploited together to achieve a greater impact than any single vulnerability could achieve alone. These can span different categories such as authentication flaws, logic vulnerabilities, and injection flaws, and are often stitched together based on application design or trust relationships.
For example: Open Redirect + Reflected XSS → Credential Theft
Attackers use chained paths to elevate privileges, move laterally, and persist inside systems without triggering obvious alerts.
Why Chained Vulnerabilities Are More Dangerous
Chained vulnerabilities represent a multiplicative risk, where individual low or medium-severity vulnerabilities, when exploited in sequence, can lead to critical-level compromise. Their real danger lies not in the severity of each vulnerability, but in how they interact under specific conditions.
1. From Low Risk to Full Compromise
Many vulnerabilities on their own may appear harmless like an open redirect or a minor information disclosure. But when paired with another vulnerability (e.g., a weak authentication mechanism), they can enable attackers to:
- Bypass access controls
- Escalate privileges
- Reach internal components or sensitive data
This chaining ability means attackers no longer rely on a single high-severity CVE. Instead, they leverage overlooked vulnerabilities in creative ways to penetrate deeper into systems.
2. Non-Linear Exploitation Patterns
Traditional vulnerability assessments often follow a linear approach: detect → assess → patch. Chained attacks break this model by exploiting non-linear logic paths:
- A reflected XSS might be used to steal a session token.
- That token might then be used to abuse an IDOR vulnerability.
- The IDOR could expose configuration files, which finally leads to RCE.
Each step alone may not raise an alarm, but together, they create a breach pathway that most tools miss.
3. Logical Gaps and Component Interplay
What makes chained vulnerabilities dangerous is that they often exploit the trust relationships between application components. These are not technical bugs in the traditional sense, they are design-level oversights:
- An API endpoint trusts requests from the front-end without validation.
- A file upload feature does not check extensions after user authentication.
- A misconfigured cloud permission allows lateral access from one microservice to another.
Attackers understand how to exploit these logical seams that occur across layers, modules, or integration points where no single component is entirely “broken,” but together they form an exploitable chain.
How Chained Exploits Typically Work
Chained attacks progress in stages, where each step builds on the last to escalate the threat:
1. Reconnaissance & Entry Point
The attacker starts by probing the application or system for small weaknesses like misconfigured headers, exposed APIs, or leaked tokens. These may not be critical alone but can offer a way in.
Example: Discovering a publicly accessible debug page with system info.
2. Privilege Escalation
Once inside, the attacker looks for ways to elevate their access such as exploiting weak session management or insecure direct object references (IDOR).
Example: Using session fixation or weak access control to impersonate an admin.
3. Lateral Movement
The attacker moves within the application or across systems, leveraging additional vulnerabilities such as SSRF (Server-Side Request Forgery), unvalidated redirects, or misconfigured services.
Example: Using SSRF to access internal cloud metadata and extract credentials.
4. Final Exploit (Impact Stage)
All steps come together in a high-impact action like data exfiltration, account takeover or remote code execution (RCE).
Example: Uploading a web shell after bypassing file validation and gaining admin access.
Even if individual vulnerabilities seem low risk, when exploited in a chain, they become critical attack paths. This is why context-aware security testing not just isolated vulnerability scans, is essential.
Common Vulnerabilities Used in Chains
Certain vulnerabilities are more likely to be used in chained attacks because of how easily they can interact with other vulnerabilities:
- LFI + Log Poisoning → Enables remote code execution through manipulated server logs.
- SSRF + Metadata API Access → Allows internal service access, often leading to token exposure.
- IDOR + Privilege Escalation → Grants unauthorized users admin-level access.
- XSS + Session Fixation or CSRF → Facilitates full account takeover via session manipulation.
- Weak Authentication + Misconfiguration → Lets attackers bypass critical access controls.
- These combinations often slip through siloed assessments. Addressing them requires a holistic view of the application’s attack surface, not just isolated patching of individual vulnerabilities.
Why Traditional Defenses Fail Against Chained Vulnerabilities
Chained vulnerabilities do not rely on a single vulnerability; they exploit how multiple vulnerabilities interact across layers and components. Traditional defenses often lack the context to connect these dots, leaving critical attack paths undetected.
1. Vulnerabilities Are Assessed in Isolation
Most traditional scanners and legacy WAF evaluate vulnerabilities independently flagging one misconfiguration or one vulnerability at a time. But attackers don’t think in silos. They piece together unrelated vulnerabilities like an LFIand insecure deserialization to escalate impact.
When tools fail to correlate these findings, the real threat goes unnoticed.
2. No Visibility Across Application Layers
Chained attacks often exploit weaknesses across the front end, backend, APIs, and infrastructure. For example, a weak frontend control might allow crafted input that passes silently into a backend job queue or serverless function.
Tools that focus only on one layer miss how data and control flow between systems, allowing critical interactions to slip through.
3. Stateful Exploit Paths Are Missed
Many exploit chains depend on user state or request history. For instance, an attacker might set a specific session state in one request and exploit it later through another endpoint. Traditional scanners are stateless; they analyze one request at a time and lack the session’s correlation required to identify such sequences.
4. Limited Detection of Business Logic and Abuse Paths
Business logic vulnerabilitie, such as reusing coupons, abusing order flows, or skipping approval steps, are difficult for automated tools to detect, especially when they involve chain actions across modules.
These are not code-level bugs but design-level oversights that attackers exploit creatively. Most traditional tools lack the contextual understanding to map these logic-based attack paths.
This is where expert-led manual pen-testing,like that integrated in Indusface WAS adds value by identifying vulnerabilities that arise from real-world usage rather than technical misconfigurations.
5. No Cross-Component Correlation
Chained attacks often abuse trust between different services or components, especially in microservice-based architectures. An attacker might use an exposed mobile API to gain access and then pivot across internal services using inconsistent authentication checks.
Traditional defenses often treat components separately and don’t track how access or actions move across the system.
6. Risk Scoring Lacks Chaining Awareness
CVSS-based prioritization looks at each vulnerability in isolation and does not account for how vulnerabilities can be exploited together. A low-scoring SSRF in a public API might be the entry point to steal tokens and access internal metadata services, leading to complete compromise.
A contextual scoring model like AcuRisQ helps fill this gap by analyzing factors like discoverability, chaining potential, and asset sensitivity to prioritize real-world risks.
7. Signature-Based Detection Falls Short
Traditional WAFs and endpoint tools often rely on predefined signatures or anomaly thresholds. Chained attacks, especially those involving logic abuse or novel sequences, rarely trigger known signatures.
Attackers exploit this blind spot to stay under the radar while combining vulnerabilities in creative ways.
Best Practices to Prevent Chained Vulnerabilities Exploitation in Web Applications
Preventing the exploitation of chained vulnerabilities requires a proactive, multi-layered security approach.
1. Map the Application’s Attack Surface Through Threat Modeling
Chained vulnerabilities often exploit the relationships between components. By performing threat modeling during the design and development stages, teams can visualize how data, permissions, and control flows interact across modules. This helps identify risky sequences and abuse paths, such as how a benign input could trigger dangerous behavior elsewhere.
2. Integrate Security Testing into CI/CD Pipelines
By shifting security testing left (into the development phase), you can catch security gaps before they are deployed. This helps spot combinations of vulnerabilities such as weak authentication + exposed endpoints that could be exploited together later.
Tools like Indusface WAS seamlessly integrate with your CI/CD pipeline, enabling automated vulnerability scanning with every code deployment to catch and prevent exploit chains before they reach production.
3. Perform Regular Penetration Testing
Automated scans can miss exploit chains. Regular manual penetration testing helps uncover logical vulnerabilities and multi-step attack paths that attackers might use.
4. Use AI and Behavioral Monitoring
Chained attacks often manifest as a series of low-noise actions. Leverage AI and anomaly detection to monitor how users interact with your application. Sudden role changes, odd API usage patterns, or unusual data access could indicate chained exploits.
5. Apply Layered, Context-Aware Security Controls
Even if one vulnerability is exploited, layered security can stop attackers from progressing further. Enforce strict input validation, output encoding, least privilege for services and users, and segmentation of internal resources. This limits lateral movement and breaks the chain mid-sequence.
6. Implement Context-Aware WAF Rules
Use a Web Application Firewall (like AppTrana WAF) that applies behavioral and contextual rules, not just signature-based blocking. This helps detect unusual sequences that indicate chaining attempts.
7. Keep Dependencies Updated
Third-party plugins or libraries with known vulnerabilities can become the starting point of a chain. Use tools to track and update them regularly.
8. Fix Root Causes, Not Just Symptoms
Patch all linked vulnerabilities, even if one seems to be the main entry point. Leaving any weak link behind could allow attackers to reconstruct the chain. Use SwyftComply to patch all open vulnerabilities and block known exploits instantly while working on permanent code fixes.
9. Ensure Centralized Logging and Correlation
Use centralized security monitoring to correlate suspicious activities across different services and layers enabling early detection of chained attempts.
How AppTrana Prevents Chained Vulnerability Exploitation
AppTrana prevents chained vulnerability exploitation by combining AI-driven detection, expert-led testing, and real-time protection. Unlike traditional tools that assess vulnerabilities in isolation, AppTrana uses a risk-based approach to analyze how seemingly low-risk vulnerabilities can be exploited together. Its AI engine continuously monitors application behavior to identify unusual patterns and sequences such as suspicious access flows or privilege escalations that often signal a chained attack in progress.
This is further enhanced by manual penetration testing from security experts, who simulate real-world attack chains and uncover complex exploitation paths. Even before the actual code is fixed, AppTrana applies intelligent virtual patching at the edge, blocking potential chained exploits using behavior and context-aware rules. With its unified dashboard, security teams gain clear visibility into correlated threats, exploit attempts, and blocked attack chains. By combining automation, AI, and expert insights, AppTrana offers a proactive, full-stack defense that stops chained vulnerabilities from escalating into breaches.
