Remote denial of service in Apache Tomcat



Published: 2021-07-29
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2021-30639
CWE-ID CWE-755
Exploitation vector Network
Public exploit N/A
Vulnerable software
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Apache Tomcat
Server applications / Web servers

Vendor Apache Foundation

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Improper Handling of Exceptional Conditions

EUVDB-ID: #VU55422

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-30639

CWE-ID: CWE-755 - Improper Handling of Exceptional Conditions

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper error management within the application when handling unexpected connection termination. A remote attacker can drop connection with the Apache Tomcat server, which triggers a non-blocking I/O error and causes all requests, handled by that request object, to fail. As a result, a remote attacker can initiate and drop connections to the server and perform a denial of service attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Apache Tomcat: 10.0.0 - 10.0.4, 9.0.0 - 9.0.44, 8.5.0 - 8.5.64


CPE2.3 External links

http://lists.apache.org/thread.html/rd84fae1f474597bdf358f5bdc0a5c453c507bd527b83e8be6b5ea3f4%40%3Cannounce.tomcat.apache.org%3E
http://lists.apache.org/thread.html/r79a7c019712b39aedf7cf4da9276d80610f04441b2a4f6506cb2daaf@%3Cusers.tomcat.apache.org%3E
http://lists.apache.org/thread.html/r79a7c019712b39aedf7cf4da9276d80610f04441b2a4f6506cb2daaf@%3Cdev.tomcat.apache.org%3E

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



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