// For flags

CVE-2023-42116

Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability

Severity Score

8.1
*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track*
*SSVC
Descriptions

Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. Was ZDI-CAN-17515.

Vulnerabilidad de ejecución remota de código de desbordamiento de búfer en la región stack de la memoria del desafío SMTP de Exim. Esta vulnerabilidad permite a atacantes remotos ejecutar código arbitrario en las instalaciones afectadas de Exim. No se requiere autenticación para aprovechar esta vulnerabilidad. La falla específica existe en el manejo de solicitudes de desafío NTLM. El problema se debe a la falta de una validación adecuada de la longitud de los datos proporcionados por el usuario antes de copiarlos en un búfer basado en pila de longitud fija. Un atacante puede aprovechar esta vulnerabilidad para ejecutar código en el contexto de la cuenta de servicio. Era ZDI-CAN-17515.

Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account.
. Was ZDI-CAN-17515.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account.

Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. . Was ZDI-CAN-17515.

It was discovered that Exim incorrectly handled certain challenge requests. A remote attacker could possibly use this issue to perform out-of-bounds reads, resulting in information leakage. It was discovered that Exim incorrectly handled validation of user-supplied data. A remote attacker could possibly use this issue to perform out-of-bounds writes, resulting in arbitrary code execution. This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS and Ubuntu 23.04.

*Credits: Anonymous
CVSS Scores
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Network
Attack Complexity
High
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:Track*
Exploitation
None
Automatable
No
Tech. Impact
Total
* Organization's Worst-case Scenario
Timeline
  • 2023-09-06 CVE Reserved
  • 2023-09-27 CVE Published
  • 2024-09-18 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-121: Stack-based Buffer Overflow
CAPEC
References (1)
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Exim
Search vendor "Exim"
Exim
Search vendor "Exim" for product "Exim"
4.95
Search vendor "Exim" for product "Exim" and version "4.95"
en
Affected