Vulnerabilities > CVE-2015-3178 - Cross-Site Scripting vulnerability in Moodle
Cross-site scripting (XSS) vulnerability in the external_format_text function in lib/externallib.php in Moodle through 2.5.9, 2.6.x before 2.6.11, 2.7.x before 2.7.8, and 2.8.x before 2.8.6 allows remote authenticated users to inject arbitrary web script or HTML into an external application via a crafted string that is visible to web services.
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Cross Site Scripting through Log Files An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
- 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.
- Cross-Site Scripting in Error Pages An attacker distributes a link (or possibly some other query structure) with a request to a third party web server that is malformed and also contains a block of exploit code in order to have the exploit become live code in the resulting error page. When the third party web server receives the crafted request and notes the error it then creates an error message that echoes the malformed message, including the exploit. Doing this converts the exploit portion of the message into to valid language elements that are executed by the viewing browser. When a victim executes the query provided by the attacker the infected error message error message is returned including the exploit code which then runs in the victim's browser. XSS can result in execution of code as well as data leakage (e.g. session cookies can be sent to the attacker). This type of attack is especially dangerous since the exploit appears to come from the third party web server, who the victim may trust and hence be more vulnerable to deception.
- Cross-Site Scripting Using Alternate Syntax The attacker uses alternate forms of keywords or commands that result in the same action as the primary form but which may not be caught by filters. For example, many keywords are processed in a case insensitive manner. If the site's web filtering algorithm does not convert all tags into a consistent case before the comparison with forbidden keywords it is possible to bypass filters (e.g., incomplete black lists) by using an alternate case structure. For example, the "script" tag using the alternate forms of "Script" or "ScRiPt" may bypass filters where "script" is the only form tested. Other variants using different syntax representations are also possible as well as using pollution meta-characters or entities that are eventually ignored by the rendering engine. The attack can result in the execution of otherwise prohibited functionality.
NASL family Fedora Local Security Checks NASL id FEDORA_2015-14996.NASL description moodle-2.7.9-1.fc21 - 2.7.9. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-05 modified 2015-09-16 plugin id 85956 published 2015-09-16 reporter This script is Copyright (C) 2015-2020 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/85956 title Fedora 21 : moodle-2.7.9-1.fc21 (2015-14996) NASL family Fedora Local Security Checks NASL id FEDORA_2015-14987.NASL description moodle-2.9.1-1.fc23 - 2.9.1 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-05 modified 2015-09-21 plugin id 86032 published 2015-09-21 reporter This script is Copyright (C) 2015-2020 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/86032 title Fedora 23 : moodle-2.9.1-1.fc23 (2015-14987) NASL family Fedora Local Security Checks NASL id FEDORA_2015-14988.NASL description moodle-2.8.7-1.fc22 - Latest upstream release. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-05 modified 2015-09-16 plugin id 85955 published 2015-09-16 reporter This script is Copyright (C) 2015-2020 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/85955 title Fedora 22 : moodle-2.8.7-1.fc22 (2015-14988)