Remote code execution in Fluent Bit

1) Out-of-bounds write

EUVDB-ID: #VU49223

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-35963

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing untrusted input within the flb_gzip_compress() function in flb_gzip.c. A remote attacker can create a specially crafted file, trick the victim into opening it using the affected software, trigger out-of-bounds write and execute arbitrary code on the target system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Fluent Bit: 1.6.0 - 1.6.3

External links

http://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27261
http://fluentbit.io/announcements/v1.6.4/
http://github.com/fluent/fluent-bit/commit/cadff53c093210404aed01c4cf586adb8caa07af

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.