Important: dovecot

Issue Overview:

In Dovecot before 2.3.11.3, sending a specially formatted RPA request will crash the auth service because a length of zero is mishandled. A flaw was found in dovecot. An attacker can use the way dovecot handles RPA (Remote Passphrase Authentication) to crash the authentication process repeatedly preventing login. The highest threat from this vulnerability is to system availability. (CVE-2020-12674)

In Dovecot before 2.3.11.3, uncontrolled recursion in submission, lmtp, and lda allows remote attackers to cause a denial of service (resource consumption) via a crafted e-mail message with deeply nested MIME parts. A flaw was found in dovecot. A remote attacker could cause a denial of service by repeatedly sending emails containing MIME parts containing malicious content of which dovecot will attempt to parse. The highest threat from this vulnerability is to system availability. (CVE-2020-12100)

In Dovecot before 2.3.11.3, sending a specially formatted NTLM request will crash the auth service because of an out-of-bounds read. A flaw was found in dovecot. An out-of-bounds read flaw was found in the way dovecot handled NTLM authentication allowing an attacker to crash the dovecot auth process repeatedly preventing login. The highest threat from this vulnerability is to system availability. (CVE-2020-12673)

Affected Packages:

dovecot

Note:

This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.

Issue Correction:
Run yum update dovecot to update your system.

New Packages:

aarch64:  
    dovecot-2.2.36-6.amzn2.1.aarch64  
    dovecot-pigeonhole-2.2.36-6.amzn2.1.aarch64  
    dovecot-pgsql-2.2.36-6.amzn2.1.aarch64  
    dovecot-mysql-2.2.36-6.amzn2.1.aarch64  
    dovecot-devel-2.2.36-6.amzn2.1.aarch64  
    dovecot-debuginfo-2.2.36-6.amzn2.1.aarch64  
  
i686:  
    dovecot-2.2.36-6.amzn2.1.i686  
    dovecot-pigeonhole-2.2.36-6.amzn2.1.i686  
    dovecot-pgsql-2.2.36-6.amzn2.1.i686  
    dovecot-mysql-2.2.36-6.amzn2.1.i686  
    dovecot-devel-2.2.36-6.amzn2.1.i686  
    dovecot-debuginfo-2.2.36-6.amzn2.1.i686  
  
src:  
    dovecot-2.2.36-6.amzn2.1.src  
  
x86_64:  
    dovecot-2.2.36-6.amzn2.1.x86_64  
    dovecot-pigeonhole-2.2.36-6.amzn2.1.x86_64  
    dovecot-pgsql-2.2.36-6.amzn2.1.x86_64  
    dovecot-mysql-2.2.36-6.amzn2.1.x86_64  
    dovecot-devel-2.2.36-6.amzn2.1.x86_64  
    dovecot-debuginfo-2.2.36-6.amzn2.1.x86_64  

Additional References

Red Hat: CVE-2020-12100, CVE-2020-12673, CVE-2020-12674

Mitre: CVE-2020-12100, CVE-2020-12673, CVE-2020-12674