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GHSA-g5w6-mrj7-75h2 CVE-2021-39141

XStream is vulnerable to an Arbitrary Code Execution attack

High Maven
Severity
8.5 / 10
High · CVSS 3.1
Exploit chance (EPSS)
16.12%
Chance of exploitation in the next 30 days. Higher than 96.92% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-502 Deserialization of Untrusted Data
Fix
1.4.18
Upgrade com.thoughtworks.xstream:xstream to this version or later

Description

Impact

The vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types.

Patches

XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.

Workarounds

See workarounds for the different versions covering all CVEs.

References

See full information about the nature of the vulnerability and the steps to reproduce it in XStream's documentation for CVE-2021-39141.

Credits

Ceclin and YXXX from the Tencent Security Response Center found and reported the issue to XStream and provided the required information to reproduce it.

For more information

If you have any questions or comments about this advisory:

Affected versions

Maven

PackageVulnerableFixed in
com.thoughtworks.xstream:xstream
< 1.4.18
1.4.18

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.

com.thoughtworks.xstream:xstream Maven → 1.4.18

maven
<dependency><groupId>com.thoughtworks.xstream</groupId><artifactId>xstream</artifactId><version>1.4.18</version></dependency>
gradle
implementation("com.thoughtworks.xstream:xstream:1.4.18")

Severity breakdown

CVSS 3.1 8.5

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

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

Weakness

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
CVE-2021-39144
XStream is vulnerable to a Remote Command Execution attack
High Known exploited Also affects com.thoughtworks.xstream:xstream
GHSA-hfq9-hggm-c56q
XStream is vulnerable to a Denial of Service attack due to stack overflow from a manipulated binary input stream
High Also affects com.thoughtworks.xstream:xstream
GHSA-f8cc-g7j8-xxpm
XStream can cause a Denial of Service by injecting deeply nested objects raising a stack overflow
High Also affects com.thoughtworks.xstream:xstream
GHSA-j563-grx4-pjpv
XStream can cause Denial of Service via stack overflow
High Also affects com.thoughtworks.xstream:xstream
GHSA-rmr5-cpv2-vgjf
Denial of Service by injecting highly recursive collections or maps in XStream
High Also affects com.thoughtworks.xstream:xstream
GHSA-64xx-cq4q-mf44
XStream is vulnerable to an Arbitrary Code Execution attack
High Also affects com.thoughtworks.xstream:xstream
GHSA-6wf9-jmg9-vxcc
XStream can cause a Denial of Service
Medium Also affects com.thoughtworks.xstream:xstream
GHSA-8jrj-525p-826v
XStream is vulnerable to an Arbitrary Code Execution attack
High Also affects com.thoughtworks.xstream:xstream
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