Dovecot Input Buffer Size Validation Arbitrary Code Execution Vulnerability [CVE-2019-7524]

CVE Number – CVE-2019-7524

A vulnerability in Dovecot could allow a local attacker to execute arbitrary code on a targeted system.

The vulnerability is due to insufficient validation and sanitization of user-supplied input by the affected software when handling Full Text Search (FTS) or Post Office Protocol Version 3 unique ID listing (POP3-UIDL) header data in Dovecot index files. The vulnerability manifests as a memory stack buffer overflow error condition. An attacker with direct write access to Dovecot index files could exploit the vulnerability by accessing the system and executing an application that submits malicious input to the affected software. A successful exploit could allow the attacker to execute arbitrary code and completely compromise the system. 

Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available. 

The Dovecot project has confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, the attacker must have user-level access to the targeted system. This access requirement could reduce the likelihood of a successful exploit.

Safeguards

• Administrators are advised to apply the appropriate updates.
  
  Administrators are advised to allow only trusted users to access local systems.
  
  Administrators are advised to allow only privileged users to access administration or management systems.
  
  Administrators are advised to monitor critical systems.

Vendor Announcements

• The Dovecot project has published a security announcement at the following link: CVE-2019-7524: Buffer overflow when reading extension header from dovecot index files

Fixed Software

• The Dovecot project has released updated software at the following link: v2.3.5.1 released