Denial of Service (DoS) Affecting org.http4s:blaze-core_2.13 package, versions [,0.14.15)


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
0.2% (59th percentile)

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  • Snyk IDSNYK-JAVA-ORGHTTP4S-1069896
  • published4 Feb 2021
  • disclosed2 Feb 2021
  • creditUnknown

Introduced: 2 Feb 2021

CVE-2021-21293  (opens in a new tab)
CWE-400  (opens in a new tab)

How to fix?

Upgrade org.http4s:blaze-core_2.13 to version 0.14.15 or higher.

Overview

Affected versions of this package are vulnerable to Denial of Service (DoS). All servers running affected versions of blaze-core are affected. Blaze accepts connections unconditionally on a dedicated thread pool. This has the net effect of amplifying degradation in services that are unable to handle their current request load, since incoming connections are still accepted and added to an unbounded queue. Each connection allocates a socket handle, which drains OS resources.

A workaround is to implement a reverse proxy that implements connection limiting before sockets reach the blaze-core instance.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

References

CVSS Base Scores

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