CVE-2018-6789
Confirmed PUBLISHEDAn issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may...
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.
- CVE Published
- Feb 08, 2018
- Exploitation Reported
- Nov 03, 2021
- CVSS
- 9.8 Critical
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| n/a |
n/a
|
n/a |
Affected |
CVE References
- USN-3565-1 usn.ubuntu.com · Vendor Advisory https://usn.ubuntu.com/3565-1/
- DSA-4110 debian.org · Vendor Advisory https://www.debian.org/security/2018/dsa-4110
- 44571 exploit-db.com · Exploit https://www.exploit-db.com/exploits/44571/
- 45671 exploit-db.com · Exploit https://www.exploit-db.com/exploits/45671/
- 1040461 securitytracker.com · VDB Entry http://www.securitytracker.com/id/1040461
Show 8 more references
- 103049 securityfocus.com · VDB Entry http://www.securityfocus.com/bid/103049
- [oss-security] 20180207 CVE-2018-6789 Exim 4.90 and earlier: buffer overflow openwall.com · Mailing List http://www.openwall.com/lists/oss-security/2018/02/07/2
- [debian-lts-announce] 20180210 [SECURITY] [DLA 1274-1] exim4 security update lists.debian.org · Mailing List https://lists.debian.org/debian-lts-announce/2018/02/msg00009.html
- exim.org/static/doc/security/CVE-2018-6789.txt exim.org · CVE Record https://exim.org/static/doc/security/CVE-2018-6789.txt
- OSS-Security Mailing List openwall.com · CVE Record http://openwall.com/lists/oss-security/2018/02/10/2
- git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c... git.exim.org · CVE Record https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855...
- devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiti... devco.re · CVE Record https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2...
- packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html packetstormsecurity.com · CVE Record http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overf...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2021-11-03 00:00 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AV:N/AC:L/Au:N/C:P/I:P/A:P
Exploitation Status
Exploited in the wild
Recorded 2021-11-03 00:00:00 UTC · CISA
Used in malware
Recorded 2021-11-03 00:00:00 UTC · CISA
Proof of concept available
Recorded 2018-11-08 08:25:42 UTC · GitHub
Weaknesses (CWE)
-
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
github · Created 2023-08-05 11:28:49 UTC · 1 stars
Exim < 4.90.1 RCE Vulnerability remake for Python3 with arguments passed from CLI
github · Created 2019-10-10 09:36:03 UTC · 9 stars
PoC materials to exploit CVE-2018-6789
github · Created 2018-11-08 08:25:42 UTC · 2 stars
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
00:00 UTC over 4 years ago00:00 UTC · over 4 years ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
00:00 UTC over 4 years ago00:00 UTC · over 4 years ago
First public exploitation report
Exploit observed in malware
-
08:25 UTC over 7 years ago08:25 UTC · over 7 years ago
Public PoC available
Public proof-of-concept code published
-
23:00 UTC over 8 years ago23:00 UTC · over 8 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC over 8 years ago00:00 UTC · over 8 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2018-6789
{
"cve_id": "CVE-2018-6789",
"title": "An issue was discovered in the base64d function in the SMTP listener in Exim ...",
"affected_vendor": "Exim",
"affected_product": "Exim",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.8,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}