Exim is an open source Mail Transfer Agent (MTA) used in an UNIX-like operating systems and is responsible for receiving, delivering and routing e-mail messages.. A Remote 'Root' Code Execution vulnerability was recently discovered in Exim servers. This vulnerability comes into picture when the Exim servers use TLS connections for communicating with the agent. The vulnerability could be used to execute arbitrary code as root via a trailing backslash-null sequence during the initial TLS handshake.
CVSS v3.0 Severity and Metrics:
Base Score: 9.8 CRITICAL
CVSS v2.0 Severity and Metrics:
Base Score: 10.0 HIGH
Exim server versions before 4.92.2
To address this vulnerability, the vendor has released patches for Exim package in all the platforms affected. For more information, please refer to our blog:
Use SanerNow platform to apply this critical patch quickly across the organization as shown below.
Vulnerability detection and patching of Exim:
- Login to SanerNow platform
- Switch to the account/site specific view and Go to 'VM tool'
- If your Application (Exim) is vulnerable, Saner lists CVE-2019-15846 in 'Top Vulnerabilities or 'Recently Discovered Vulnerabilities as shown in the below diagram:
- Search for this vulnerability in VM tool. If you are affected, apply the patch through PM -> Missing Patches.
- Select 'Groups/Devices in the 'Asset Source' section and click 'Apply'.
- Select the product 'Exim' from the 'Asset' section as shown in the below diagram:
7. Select ‘Apply Selected Patches’ at the rightmost corner. This will prompt for ‘Creating Patch Task’. Fill in ‘Task Name’ and ‘Remediation Schedule as per your preference and click on ‘Apply Selected Patches as shown below:
- Remediation job will be created, which will fix the vulnerability by upgrading Exim to the latest patch version.
- Once remediation is done, the Saner agent automatically scans again and uploads the result to SanerNow as shown below: