CVE-2018-6789 on CISA KEV

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.

01What CISA says about this vulnerability

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.

02Required action — verbatim from CISA

Apply updates per vendor instructions.

03Notes & references

• exim.org — https://exim.org/static/doc/security/CVE-2018-6789.txt
• www.openwall.com — http://www.openwall.com/lists/oss-security/2018/02/07/2
• usn.ubuntu.com — https://usn.ubuntu.com/3565-1/
• openwall.com — http://openwall.com/lists/oss-security/2018/02/10/2
• www.securitytracker.com — http://www.securitytracker.com/id/1040461
• www.debian.org — https://www.debian.org/security/2018/dsa-4110
• www.exploit-db.com — https://www.exploit-db.com/exploits/44571/
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2018/02/msg00009.html
• git.exim.org — https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1
• devco.re — https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en…
• www.securityfocus.com — http://www.securityfocus.com/bid/103049
• www.exploit-db.com — https://www.exploit-db.com/exploits/45671/
• packetstormsecurity.com — http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html

04SARA's analyst layer — why this matters

This vulnerability is currently on the CISA KEV list, which CISA only adds CVEs to when there is reliable evidence of active exploitation in the wild. For federal civilian agencies, BOD 22-01 requires remediation by the due date above. For everyone else, KEV is the strongest "patch immediately" signal you can get from public threat intel.

05Affected products (summary)

Vendor	Product	Versions
n	a / n/a	n/a

06Detection

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