How the CVE Works
CVE-2025-21587 is a critical vulnerability in Oracle Java SE’s JSSE (Java Secure Socket Extension) component, affecting multiple versions. The flaw stems from improper TLS/SSL handshake validation, allowing attackers to exploit weak cryptographic operations or bypass authentication. By manipulating network traffic via MITM (Man-in-the-Middle) attacks, an attacker can inject malicious packets during the handshake phase, leading to data tampering or unauthorized access. The vulnerability is difficult to exploit but critical due to its impact on confidentiality and integrity.
DailyCVE Form
Platform: Oracle Java SE
Version: 8u441, 11.0.26, 17.0.14, 21.0.6, 24
Vulnerability: TLS/SSL Handshake Bypass
Severity: Critical
Date: 04/30/2025
What Undercode Say:
Exploitation:
1. MITM Attack Setup:
sslsplit -D -l /var/log/sslsplit.log -j /tmp/sslsplit -S /tmp/ssl -k ca.key -c ca.crt ssl 0.0.0.0 8443 tcp 0.0.0.0 8080
2. Forced Downgrade Attack:
from scapy.all import pkts = sniff(filter="tcp port 443", count=100) pkts[bash].show() Analyze handshake
Protection:
1. Update Java:
sudo apt update && sudo apt upgrade openjdk-17-jdk
2. Disable Weak Ciphers:
Security.setProperty("jdk.tls.disabledAlgorithms", "SSLv3, TLSv1, TLSv1.1, RC4, DES");
3. Network Hardening:
iptables -A INPUT -p tcp --dport 443 -m conntrack --ctstate NEW -m recent --set
Detection:
1. Log Analysis:
grep "HandshakeFailure" /var/log/java/security.log
2. NMAP Scan:
nmap --script ssl-enum-ciphers -p 443 target.com
Mitigation:
- Enforce TLS 1.2+ only.
- Use certificate pinning in Java apps.
- Monitor JSSE logs for anomalies.
References:
- Oracle Patch: Oracle Advisory
- CVSS 4.0 Vector: `CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
