Squid HttpHeader::getAuth Basic Authentication Heap-Based Buffer Overflow Vulnerability [CVE-2019-12527]

CVE Number – CVE-2019-12527

A vulnerability in Squid could allow an unauthenticated, remote attacker to execute arbitrary code or cause a denial of service (DoS) condition on a targeted system. The vulnerability is due to a heap-based buffer overflow condition that exists in the HttpHeader::getAuth function of the affected software when checking basic authentication. An attacker could exploit this vulnerability by submitting a crafted HTTP request to the targeted system. A successful exploit could allow the attacker to execute arbitrary code or cause a DoS condition on the targeted system. Squid has confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, an attacker must send an HTTP request that submits malicious input to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.

Safeguards

• Administrators are advised to apply the appropriate updates.
  
  Administrators are advised to allow only trusted users to have network access.
  
  Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.
  
  Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
  
  Administrators can help protect affected systems from external attacks by using a solid firewall strategy.
  
  Administrators are advised to monitor affected systems.

Vendor Announcements

• Squid has released a commit at the following link: Commit 44a4677f9ff34c04b14bb2c131afd6cb1e18c335

Fixed Software

• Squid has released a software patch at the following link: Update HttpHeader::getAuth to SBuf (#416)