#VU59051 Infinite loop in Apache Log4j - CVE-2021-45105
Published: December 18, 2021 / Updated: February 9, 2023
Vulnerability identifier: #VU59051
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/U:Green
CVE-ID: CVE-2021-45105
CWE-ID: CWE-835
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vulnerable software:
Apache Log4j
Apache Log4j
Software vendor:
Apache Foundation
Apache Foundation
Description
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to infinite loop within the StrSubstitutor class. A remote attacker can pass specially crafted input to the application, consume all available system resources and cause denial of service conditions.
Payload example: ${${::-${::-$${::-j}}}}
Remediation
Install updates from vendor's website.