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CAPEC-81: Web Logs Tampering

 
Web Logs Tampering
Definition in a New Window Definition in a New Window
Attack Pattern ID: 81
Abstraction: Standard
Status: Draft
Completeness: Complete
+ Description

Summary

Web Logs Tampering attacks involve an attacker injecting, deleting or otherwise tampering with the contents of web logs typically for the purposes of masking other malicious behavior. Additionally, writing malicious data to log files may target jobs, filters, reports, and other agents that process the logs in an asynchronous attack pattern. This pattern of attack is similar to "Log Injection-Tampering-Forging" except that in this case, the attack is targeting the logs of the web server and not the application.

Attack Execution Flow

Explore
  1. Determine Application Web Server Log File Format:

    The attacker observes the system and looks for indicators of which logging utility is being used by the web server.

    Attack Step Techniques

    IDAttack Step Technique DescriptionEnvironments
    1

    Determine logging utility being used by application web server (e.g. log4j), only possible if the application is known by the attacker or if the application returns error messages with logging utility information.

    env-Web

    Outcomes

    IDTypeOutcome Description
    1Success
    Attacker determines log file format used by application web server.
    2Inconclusive
    Attacker cannot conclusively determine log file format; he/she can only guess what the format is.
Experiment
  1. Determine Injectable Content:

    The attacker launches various logged actions with malicious data to determine what sort of log injection is possible.

    Attack Step Techniques

    IDAttack Step Technique DescriptionEnvironments
    1

    Attacker triggers logged actions with maliciously crafted data as inputs, parameters, arguments, etc.

    env-Web

    Outcomes

    IDTypeOutcome Description
    1Success
    Attacker observes content successfully injected into web logs.
    2Inconclusive
    Attacker lacks capability to observe if content was successfully injected into web logs.
Exploit
  1. Manipulate Log Files:

    The attacker alters the log contents either directly through manipulation or forging or indirectly through injection of specially crafted request that the web server will receive and write into the logs. This type of attack typically follows another attack and is used to try to cover the traces of the previous attack.

    Attack Step Techniques

    IDAttack Step Technique DescriptionEnvironments
    1

    Indirectly through injection, 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: The HTTP request for "/index.html%0A%0DIP_ADDRESS- - DATE_FORMAT] "GET /forged-path HTTP/1.1" 200 - "-" USER_AGENT" may add the log line into Apache "access_log" (for example). Different applications may require different encodings of the carriage return and line feed characters.

    env-Web
    2

    Directly through log file or database manipulation, 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: The HTTP request for "/index.html%0A%0DIP_ADDRESS- - DATE_FORMAT] "GET /forged-path HTTP/1.1" 200 - "-" USER_AGENT" may add the log line into Apache "access_log" (for example). Different applications may require different encodings of the carriage return and line feed characters.

    env-Web
    3

    Directly through log file or database manipulation, modify existing log entries.

    env-Web

    Outcomes

    IDTypeOutcome Description
    1Success
    Forged entry or other malicious data inserted into application's logs.
    2Failure
    No entry inserted into logs, or the entry is visibly distinguishable from real entries.

    Security Controls

    IDTypeSecurity Control Description
    1Preventative
    Input validation to ensure that only legal characters supplied by users can be entered into log files
    2Preventative
    Encode information from user such that any unexpected characters are encoded safely before they are entered into log files.
    3Preventative
    Post-processing of log files to remove or encode dangerous characters before displaying to a user may help in some cases. It will not help remove fake log entries entered using carriage return and line feed characters, however.
+ Attack Prerequisites
  • Target server software must be a HTTP server that performs web logging.

+ Typical Severity

High

+ Typical Likelihood of Exploit

Likelihood: Medium

+ Methods of Attack
  • Modification of Resources
  • Time and State
+ Examples-Instances

Description

Most web servers have a public interface, even if the majority of the site is password protected, there is usually at least a login site and brochureware that is publicly available. HTTP requests to the site are also generally logged to a Web log. From an attacker point of view, standard HTTP requests containing a malicious payload can be sent to the public website (with no other access required), when those requests appear in the log (such as http://victimsite/index.html?< malicious script> if they are followed by an administrator this may be sufficient to probe the administrator's host or local network.

+ Attacker Skills or Knowledge Required

Skill or Knowledge Level: Low

To input faked entries into Web logs

+ Resources Required

Ability to send specially formatted HTTP request to web server

+ Solutions and Mitigations

Design: Use input validation before writing to web log

Design: Validate all log data before it is output

+ Attack Motivation-Consequences
ScopeTechnical ImpactNote
Integrity
Modify application data
+ Injection Vector

Forged log entry delivered through HTTP Request.

+ Payload

HTTP request

+ Activation Zone

Web log, log reporting systems

+ Payload Activation Impact

Description

Log data contains data designed to trick administrators and auditors as to chain of events. Limit ability to conduct forensics and other investigations/responses.

+ Purposes
  • Obfuscation
+ CIA Impact
Confidentiality Impact: MediumIntegrity Impact: HighAvailability Impact: Medium
+ Technical Context
Architectural Paradigms
Client-Server
SOA
Frameworks
All
Platforms
All
Languages
All
+ References
[R.81.1] [REF-2] G. Hoglund and G. McGraw. "Exploiting Software: How to Break Code". Addison-Wesley. February 2004.
+ Content History
Submissions
SubmitterOrganizationDateSource
CAPEC Content TeamThe MITRE Corporation2014-06-23Internal_CAPEC_Team

Page Last Updated: July 23, 2014