CVE-2016-3718
Description
A server-side request forgery flaw was discovered in the way ImageMagick processed certain images. A remote attacker could exploit this flaw to mislead an application using ImageMagick or an unsuspecting user using the ImageMagick utilities into, for example, performing HTTP(S) requests or opening FTP sessions via specially crafted images.
Mitigation
Details can be found under the resolve tab at https://access.redhat.com/security/vulnerabilities/2296071
Red Hat Enterprise Linux 6 and 7
================================
As a workaround the /etc/ImageMagick/policy.xml file can be edited to disable processing of MVG, HTTPS, HTTP, URL, FTP, EPHEMERAL, MSL, LABEL, TEXT,
SHOW, WIN and PLT commands within image files, simply add the following lines:
<policy domain="coder" rights="none" pattern="EPHEMERAL" />
<policy domain="coder" rights="none" pattern="HTTPS" />
<policy domain="coder" rights="none" pattern="HTTP" />
<policy domain="coder" rights="none" pattern="URL" />
<policy domain="coder" rights="none" pattern="FTP" />
<policy domain="coder" rights="none" pattern="MVG" />
<policy domain="coder" rights="none" pattern="MSL" />
<policy domain="coder" rights="none" pattern="TEXT" />
<policy domain="coder" rights="none" pattern="LABEL" />
<policy domain="coder" rights="none" pattern="SHOW" />
<policy domain="coder" rights="none" pattern="WIN" />
<policy domain="coder" rights="none" pattern="PLT" />
<policy domain="path" rights="none" pattern="@*" />
within the policy map stanza:
<policymap>
...
</policymap>
Red Hat Enterprise Linux 5
==========================
In the following folders:
/usr/lib64/ImageMagick-6.2.8/modules-Q16/coders/ (64bit package)
or
/usr/lib/ImageMagick-6.2.8/modules-Q16/coders/ (32bit package)
Rename the following files:
* mvg.so to mvg.so.bak
* msl.so to msl.so.bak
* label.so to label.so.bak
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.3 | 4.3 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Medium | Medium | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | None | None | N/A |
| Integrity Impact | Partial | Partial | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: AV:N/AC:M/Au:N/C:N/I:P/A:N
NVD: AV:N/AC:M/Au:N/C:N/I:P/A:N
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Non-Repudiation,Access Control
Technical Impact: Gain Privileges or Assume Identity; Bypass Protection Mechanism; Read Application Data; Modify Application Data; DoS: Crash, Exit, or Restart
The consequences will vary depending on the nature of the functionality that is vulnerable to CSRF. An attacker could trick a client into making an unintentional request to the web server via a URL, image load, XMLHttpRequest, etc., which would then be treated as an authentic request from the client - effectively performing any operations as the victim, leading to an exposure of data, unintended code execution, etc. If the victim is an administrator or privileged user, the consequences may include obtaining complete control over the web application - deleting or stealing data, uninstalling the product, or using it to launch other attacks against all of the product's users. Because the attacker has the identity of the victim, the scope of CSRF is limited only by the victim's privileges.
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