SB2018030602 - Gentoo update for Exim
Published: March 6, 2018
Security Bulletin ID
SB2018030602
CSH Severity
High
Patch available
YES
Number of vulnerabilities
3
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 vulnerabilities.
1) Use-after-free error (CVE-ID: CVE-2017-16943)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The weakness exists due to a use-after-free memory error in the ESMTP CHUNKING extension within the receive_msg() function in receive.c. A remote attacker can connect to the SMTP service, send a specially crafted BDAT command, trigger memory corruption and execute arbitrary code on the target system.
Successful exploitation of the vulnerability may result in system compromise.
2) Infinite loop (CVE-ID: CVE-2017-16944)
CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote attacker to cause DoS condition on the target system.
The weakness exists due to infinite loop in bdat_getc(). A remote attacker can connect to the SMTP service, send a specially crafted BDAT command, consume all available stack memory and cause the service to crash.
Successful exploitation of the vulnerability results in denial of service.
3) Buffer overflow (CVE-ID: CVE-2018-6789)
CWE-ID: CWE-120 - Buffer overflow
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The weakness exists in the SMTP listener due to improper bounds checking. A remote attacker can send a specially crafted message, trigger buffer overflow and execute arbitrary code with privileges of the Exim user.
Successful exploitation of the vulnerability may result in system compromise.
Remediation
Install update from vendor's website.