#VU22642 Buffer Over-read in tnef - CVE-2019-18849

Vulnerability identifier: #VU22642

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2019-18849

CWE-ID: CWE-126

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
tnef
Universal components / Libraries / Libraries used by multiple products

Vendor: verdammelt

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to the heap-based buffer over-read involving strdup. A remote attacker can write to the victim's ".ssh/authorized_keys" file via an e-mail message with a crafted winmail.dat application/ms-tnef attachment and crash the application.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

tnef: 1.4.10 - 1.4.17

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External links
https://github.com/verdammelt/tnef/compare/1.4.17...1.4.18
https://github.com/verdammelt/tnef/pull/40

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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