Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.
CWE-779 Base Draft
Logging of Excessive Data
This vulnerability occurs when an application records more information than necessary in its logs, making log files difficult to analyze and potentially slowing down incident response or security…
Definition
What is CWE-779?
This vulnerability occurs when an application records more information than necessary in its logs, making log files difficult to analyze and potentially slowing down incident response or security investigations.
While comprehensive logging is essential for debugging during development, excessive logging in a live production environment creates significant operational problems. Overly verbose logs can overwhelm system administrators, making it harder to spot genuine security alerts or performance issues amidst the noise. This clutter can inadvertently provide cover for an attacker, as critical malicious activity gets lost in a flood of irrelevant data.
From a security perspective, excessive logging also complicates forensic analysis after a breach, as investigators must sift through mountains of data to find relevant events. Furthermore, it can impact system performance and storage costs, and may even lead to accidentally recording sensitive information (like passwords or personal data), creating additional security risks. The goal is to implement smart, targeted logging that captures what you need without drowning you in data.
Real-world impact
Real-world CVEs caused by CWE-779
-
server records a large amount of data to the server log when it receives malformed headers
-
chain: application does not restrict access to front-end for updates, which allows attacker to fill the error log
How attackers exploit it
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable code example
Vulnerable pseudo
MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
// Untrusted input flows directly into the sensitive sink.
return executeUnsafe(input);
} Secure code example
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-779
- Architecture and Design Suppress large numbers of duplicate log messages and replace them with periodic summaries. For example, syslog may include an entry that states "last message repeated X times" when recording repeated events.
- Architecture and Design Support a maximum size for the log file that can be controlled by the administrator. If the maximum size is reached, the admin should be notified. Also, consider reducing functionality of the product. This may result in a denial-of-service to legitimate product users, but it will prevent the product from adversely impacting the entire system.
- Implementation Adjust configurations appropriately when the product is transitioned from a debug state to production.
Detection signals
How to detect CWE-779
Run dynamic application security testing against the live endpoint.
Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.
Code review: flag any new code that handles input from this surface without using the validated framework helpers.
CWE-779
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Frequently asked questions What is CWE-779?
How serious is CWE-779?
What languages or platforms are affected by CWE-779?
How can I prevent CWE-779?
How does Plexicus detect and fix CWE-779?
Where can I learn more about CWE-779?
Frequently asked questions
What is CWE-779?
This vulnerability occurs when an application records more information than necessary in its logs, making log files difficult to analyze and potentially slowing down incident response or security investigations.
How serious is CWE-779?
MITRE rates the likelihood of exploit as Low — exploitation is uncommon, but the weakness should still be fixed when discovered.
What languages or platforms are affected by CWE-779?
MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.
How can I prevent CWE-779?
Suppress large numbers of duplicate log messages and replace them with periodic summaries. For example, syslog may include an entry that states "last message repeated X times" when recording repeated events. Support a maximum size for the log file that can be controlled by the administrator. If the maximum size is reached, the admin should be notified. Also, consider reducing functionality of the product. This may result in a denial-of-service to legitimate product users, but it will prevent…
How does Plexicus detect and fix CWE-779?
Plexicus's SAST engine matches the data-flow signature for CWE-779 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-779?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/779.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-779
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