Denial of service in Exim

1) Infinite loop

EUVDB-ID: #VU9428

Risk: Low

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-16944

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Exploit availability: No

Description

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.

Mitigation

Update to version 4.90.

Vulnerable software versions

Exim: 4.88 - 4.89

External links

http://git.exim.org/exim.git/commit/4e6ae6235c68de243b1c2419027472d7659aa2b4

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.