Amazon Linux AMI update for libfastjson

1) Out-of-bounds write

EUVDB-ID: #VU27882

Risk: High

CVSSv4.0: 7.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber]

CVE-ID: CVE-2020-12762

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 in the "printbuf_memappend". A remote attacker can create a specially crafted JSON 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

Update the affected packages:

aarch64:
    libfastjson-debugsource-0.99.9-1.amzn2023.0.3.aarch64
    libfastjson-debuginfo-0.99.9-1.amzn2023.0.3.aarch64
    libfastjson-devel-0.99.9-1.amzn2023.0.3.aarch64
    libfastjson-0.99.9-1.amzn2023.0.3.aarch64

src:
    libfastjson-0.99.9-1.amzn2023.0.3.src

x86_64:
    libfastjson-debuginfo-0.99.9-1.amzn2023.0.3.x86_64
    libfastjson-debugsource-0.99.9-1.amzn2023.0.3.x86_64
    libfastjson-0.99.9-1.amzn2023.0.3.x86_64
    libfastjson-devel-0.99.9-1.amzn2023.0.3.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

libfastjson: All versions

CPE2.3

• cpe:2.3:o:amazon_web_services:amazon_linux_ami:*:*:*:*:*:*:*:*
• cpe:2.3:a:amazon_web_services:libfastjson:*:*:*:*:*:amazon_linux_ami:*:*

External links

https://alas.aws.amazon.com/AL2023/ALAS-2023-205.html

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. However, proof of concept for this vulnerability is available.