Certified: The Security+ Prepcast

In this episode, we are examining indicators of application-level attacks. These attacks often begin with subtle signs—strange logs, unexpected input behavior, or irregular access requests—but they can escalate quickly into full-scale breaches if not detected and stopped. We'll focus on signs of injection and buffer overflow attacks, session replay and privilege escalation attempts, and application manipulation techniques like forgery and directory traversal.
Let’s start with injection and buffer overflow attacks. These types of attacks exploit how applications handle input. In an injection attack, an attacker supplies specially crafted input to trick the system into executing unintended commands. SQL injection and command injection are common examples. In a buffer overflow attack, the attacker sends more data than a program expects, overwriting adjacent memory and potentially executing malicious code.
Indicators of these attacks often include system crashes, unexpected application errors, or abnormal entries in server logs. You might see long, unusual input strings passed to fields that normally expect short responses. A login page that suddenly throws server errors or displays unexpected output may be under active attack. Logs may show special characters like single quotes, semicolons, or script tags that indicate attempts to inject commands.
To protect against injection and buffer overflows, developers should use secure coding practices—starting with input validation. All user input should be sanitized, checked for length and format, and passed through filtering routines before being processed. Parameterized queries should be used for database operations to prevent SQL injection. For buffer overflows, coding languages and compilers that enforce memory safety are preferable, and stack protection features like canaries can help detect overflows before they can be exploited.
Now let’s turn to replay and privilege escalation attacks. In a replay attack, the attacker captures a valid communication or session token and resends it to impersonate a legitimate user. Privilege escalation involves exploiting application flaws or misconfigurations to gain higher access than originally intended.
Indicators of replay attacks include repeated login attempts using the same token, session IDs appearing in multiple places or from multiple locations, and unexpected session timeouts or resets. You may notice users being logged in from two locations at the same time or alerts showing the same user performing actions outside their normal behavior profile.
For privilege escalation, the signs may include sudden changes in user roles, access to administrative features by non-admin users, or execution of privileged functions without proper authentication. Logs might show a user creating new accounts, modifying configurations, or accessing restricted files without triggering expected approval workflows.
Countermeasures for these attacks include using secure session management protocols, incorporating nonces or time-stamped tokens, and applying multi-factor authentication. Monitoring tools should flag unusual account activity, and access control systems should enforce the principle of least privilege—ensuring users only have the permissions they need for their role. Response strategies include revoking active sessions, resetting passwords, and conducting audits to identify affected users and systems.
Finally, let’s look at forgery and directory traversal attacks. Forgery attacks involve tricking an application into performing actions on behalf of a user without their consent. Cross-site request forgery is one example, where a user’s browser unknowingly submits commands to a site they are logged into. Directory traversal involves manipulating input paths to gain unauthorized access to files outside the application’s normal directory structure.
Indicators of forgery attacks include unexpected application behavior initiated from authenticated sessions, commands that appear to be issued without corresponding user actions, or changes made by accounts that should not have had access. You may also find signs of requests being made from third-party domains or parameters being passed without validation.
For directory traversal, you may notice file paths with sequences like dot dot slash—used to climb back up a directory tree. Access logs may show attempts to reach configuration files, password files, or system-level logs. If a user is accessing resources they shouldn’t, or the application is returning raw file contents instead of expected data, traversal may be in progress.
To defend against these threats, input validation once again plays a critical role. File paths, parameters, and form data should be strictly validated and sanitized. Applications should never directly incorporate user input into file paths or URLs. Additionally, development teams should use security libraries and frameworks that include protections against common attack patterns. Tools like web application firewalls can detect and block known forgery and traversal signatures before they reach the backend systems.
As you prepare for the Security Plus exam, remember that application-level indicators often show up first in logs, user reports, or performance issues. You may be asked to interpret a situation where session tokens are reused, where a user gains administrative access unexpectedly, or where file paths reveal attempts to reach protected system files. Be ready to recommend input validation, role-based access controls, and secure session management as effective countermeasures for these threats.