The product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file.
View on MITREInterpretation of the log files may be hindered or misdirected if an attacker can supply data to the application that is subsequently logged verbatim. In the most benign case, an attacker may be able to insert false entries into the log file by providing the application with input that includes appropriate characters. Forged or otherwise corrupted log files can be used to cover an attacker's tracks, possibly by skewing statistics, or even to implicate another party in the commission of a malicious act. If the log file is processed automatically, the attacker can render the file unusable by corrupting the format of the file or injecting unexpected characters. An attacker may inject code or other commands into the log file and take advantage of a vulnerability in the log processing utility.
No mitigation information available for this CWE.
No detection method information available for this CWE.
The following web application code attempts to read an integer value from a request object. If the parseInt call fails, then the input is logged with an error message indicating what happened.
If a user submits the string "twenty-one" for val, the following entry is logged:
CWE-117: Improper Output Neutralization for Logs is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file.
If exploited, CWE-117 (Improper Output Neutralization for Logs) it can compromise Integrity, Confidentiality, Availability and Non-Repudiation, leading to outcomes such as Modify Application Data, Hide Activities and Execute Unauthorized Code or Commands.
CWE-117 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.
MITRE documents real CVEs mapped to CWE-117, including CVE-2006-4624. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
A CWE (Common Weakness Enumeration) like CWE-117 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.