Exploited vulnerability · CISA KEV

Is CVE-2018-6789 exploited? Yes: in CISA KEV since 3 Nov 2021

Gociux · Exim · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2018-6789, Exim Buffer Overflow Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 3 Nov 2021, 1364 days after it was published. It is known to be used in ransomware campaigns. It affects Exim. If you run it, CISA's required action is: Apply updates per vendor instructions.

What it is

Exim contains a buffer overflow vulnerability in the base64d function part of the SMTP listener that may allow for remote code execution.

What to do

1. Check whether you run it. Look for Exim in your asset inventory, including appliances and cloud images. Stack check lists every exploited Exim CVE at once.
2. Apply the fix. Apply updates per vendor instructions.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 8 Feb 2018.
4. Get told next time. Email alerts when CISA adds a CVE for Exim.

Other exploited CVEs in Exim

• CVE-2010-4345: Exim Privilege Escalation Vulnerability (25 Mar 2022)
• CVE-2010-4344: Exim Heap-Based Buffer Overflow Vulnerability (25 Mar 2022)

References

• nvd.nist.gov/vuln/detail/CVE-2018-6789

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in November 2021 · Exim scorecard · act-now radar.