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DRUPAL-CORE-2019-007 CVE-2019-11831 GHSA-xv7v-rf6g-xwrc

Directory Traversal in typo3/phar-stream-wrapper

Critical Packagist
Severity
9.8 / 10
Critical · CVSS 3.1
Exploit chance (EPSS)
5.44%
Chance of exploitation in the next 30 days. Higher than 92.72% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-502 Deserialization of Untrusted Data
Fix
Available
3 packages have a fixed version

Description

This security release fixes third-party dependencies included in or required by Drupal core. As described in TYPO3-PSA-2019-007: By-passing protection of Phar Stream Wrapper Interceptor:

In order to intercept file invocations like file_exists or stat on compromised Phar archives the base name has to be determined and checked before allowing to be handled by PHP Phar stream handling. [...]

The current implementation is vulnerable to path traversal leading to scenarios where the Phar archive to be assessed is not the actual (compromised) file.

The known vulnerability in Drupal core requires the "administer themes" permission. However, additional vulnerabilities may exist in contributed or custom modules, so site should still update even if they do not grant this permission.

Affected versions

Packagist

PackageVulnerableFixed in
drupal/core
>= 8.0.0, < 8.6.16
>= 8.7.0, < 8.7.1
8.6.16
8.7.1
drupal/core
>= 7.0.0, < 7.67.0
7.67.0
drupal/core
>= 8.0.0, < 8.6.16
8.6.16
drupal/core
>= 8.7.0, < 8.7.1
8.7.1
drupal/drupal
>= 7.0.0, < 7.67.0
7.67.0
drupal/drupal
>= 8.0.0, < 8.6.16
8.6.16
drupal/drupal
>= 8.7.0, < 8.7.1
8.7.1
typo3/phar-stream-wrapper
>= 2.0.0, < 2.1.1
2.1.1
typo3/phar-stream-wrapper
>= 3.0.0, < 3.1.1
3.1.1

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

drupal/core Packagist → 8.7.1

composer
composer require drupal/core:^8.7.1

drupal/drupal Packagist → 7.67.0

composer
composer require drupal/drupal:^7.67.0

typo3/phar-stream-wrapper Packagist → 2.1.1

composer
composer require typo3/phar-stream-wrapper:^2.1.1

Severity breakdown

CVSS 3.1 9.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Weakness

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

How to prevent it
  • Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would b
  • Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked. Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59). This includes: realpath() in C getCanonicalPath() in Java GetFullPath() in ASP.NET realpath() or abs_path() in Perl realpath() in PHP
  • Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
  • Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
  • Architecture and Design, Operation: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
  • Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap [REF-185] provide this capability.
  • Architecture and Design, Operation: Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software. OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
  • Architecture and Design, Operation: Store library, include, and utility files outside of the web document root, if possible. Otherwise, store them in a separate directory and use the web server's access control capabilities to prevent attackers from directly requesting them. One common practice is to define a fixed constant in each calling program, then check for the existence of the constant in the library/include file; if the constant does not exist, then the file was directly requested, and it can exit immediately. This significantly reduces the chance of an attacker being able to bypass any protection mechanisms that are in the base program but not in the include files. It will also reduce the attack surface.
  • Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not. In the context of path traversal, error messages which disclose path information can help attackers craft the appropriate attack strings to move through the file system hierarchy.
  • Operation, Implementation: When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.

CWE-502: Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

How to prevent it
  • Architecture and Design, Implementation: If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
  • Implementation: When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
  • Implementation: Explicitly define a final object() to prevent deserialization.
  • Architecture and Design, Implementation: Make fields transient to protect them from deserialization. An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.
  • Implementation: Avoid having unnecessary types or gadgets (a sequence of instances and method invocations that can self-execute during the deserialization process, often found in libraries) available that can be leveraged for malicious ends. This limits the potential for unintended or unauthorized types and gadgets to be leveraged by the attacker. Add only acceptable classes to an allowlist. Note: new gadgets are constantly being discovered, so this alone is not a sufficient mitigation.
  • Architecture and Design, Implementation: Employ cryptography of the data or code for protection. However, it's important to note that it would still be client-side security. This is risky because if the client is compromised then the security implemented on the client (the cryptography) can be bypassed.
  • Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

References

Advisories

Packages

Other links

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
DRUPAL-CORE-2026-004
Drupal Core has a SQL Injection issue
Critical Known exploited Also affects drupal/core
CVE-2020-28949
Multiple vulnerabilities through filename manipulation in Archive_Tar
High Known exploited Also affects drupal/core
CVE-2020-13671
Drupal core Unrestricted Upload of File with Dangerous Type
High Known exploited Also affects drupal/core
CVE-2019-6340
Drupal Core Remote Code Execution Vulnerability
High Known exploited Also affects drupal/core
CVE-2018-7602
Drupal Core Remote Code Execution Vulnerability
Critical Known exploited Also affects drupal/core
CVE-2018-7600
Drupal Core Remote Code Execution Vulnerability
Critical Known exploited Also affects drupal/core
DRUPAL-CORE-2026-016
The Navigation module doesn't sufficiently sanitize certain attributes, which can lead to a cross-site scripting (XSS) vulnerability.
Not rated yet Also affects drupal/core
DRUPAL-CORE-2026-015
The Drupal core Link module provides a field type that can be used for internal and external URLs.
Not rated yet Also affects drupal/core

Credits: Daniel Le Gall

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