Vulnerabilities > CVE-2023-32712 - Improper Encoding or Escaping of Output vulnerability in Splunk
Summary
In Splunk Enterprise versions below 9.1.0.2, 9.0.5.1, and 8.2.11.2, an attacker can inject American National Standards Institute (ANSI) escape codes into Splunk log files that, when a vulnerable terminal application reads them, can potentially, at worst, result in possible code execution in the vulnerable application. This attack requires a user to use a terminal application that supports the translation of ANSI escape codes to read the malicious log file locally in the vulnerable terminal, and to perform additional user interaction to exploit. Universal Forwarder versions 9.1.0.1, 9.0.5, 8.2.11, and lower can be vulnerable in situations where they have management services active and accessible over the network. Universal Forwarder versions 9.0.x and 9.1.x bind management services to the local machine and are not vulnerable in this specific configuration. See SVD-2022-0605 for more information. Universal Forwarder versions 9.1 use Unix Domain Sockets (UDS) for communication, which further reduces the potential attack surface. The vulnerability does not directly affect Splunk Enterprise or Universal Forwarder. The indirect impact on Splunk Enterprise and Universal Forwarder can vary significantly depending on the permissions in the vulnerable terminal application and where and how the user reads the malicious log file. For example, users can copy the malicious file from the Splunk Enterprise instance and read it on their local machine.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Cross Zone Scripting An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
- Embedding Scripts in Non-Script Elements This attack is a form of Cross-Site Scripting (XSS) where malicious scripts are embedded in elements that are not expected to host scripts such as image tags (<img>), comments in XML documents (< !-CDATA->), etc. These tags may not be subject to the same input validation, output validation, and other content filtering and checking routines, so this can create an opportunity for an attacker to tunnel through the application's elements and launch a XSS attack through other elements. As with all remote attacks, it is important to differentiate the ability to launch an attack (such as probing an internal network for unpatched servers) and the ability of the remote attacker to collect and interpret the output of said attack.
- Simple Script Injection An attacker embeds malicious scripts in content that will be served to web browsers. The goal of the attack is for the target software, the client-side browser, to execute the script with the users' privilege level. An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute code and scripts. Web browsers, for example, have some simple security controls in place, but if a remote attacker is allowed to execute scripts (through injecting them in to user-generated content like bulletin boards) then these controls may be bypassed. Further, these attacks are very difficult for an end user to detect.
- User-Controlled Filename An attack of this type involves an attacker inserting malicious characters (such as a XSS redirection) into a filename, directly or indirectly that is then used by the target software to generate HTML text or other potentially executable content. Many websites rely on user-generated content and dynamically build resources like files, filenames, and URL links directly from user supplied data. In this attack pattern, the attacker uploads code that can execute in the client browser and/or redirect the client browser to a site that the attacker owns. All XSS attack payload variants can be used to pass and exploit these vulnerabilities.
- Web Logs Tampering 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.