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How the CVE Works
The vulnerability arises in Fess’s `SystemHelper` class, where the `createTempFile()` method generates temporary files without enforcing proper file permissions. By default, these files inherit broad permissions, making them readable by any local user. Attackers exploiting this flaw can access sensitive data (e.g., search indices, session tokens) stored in these files. The issue escalates in shared hosting or multi-tenant deployments, where low-privileged users can read files owned by the Fess service account.
DailyCVE Form
Platform: Fess
Version: <13.10
Vulnerability: Insecure Temp Files
Severity: Medium
Date: 2023-01-15
Prediction: Patch by 2023-03-20
What Undercode Say:
Exploitation:
1. Local Enumeration:
find /tmp -name "fess-" -perm -o=r -ls
2. Data Exfiltration:
cat /tmp/fess-1234.tmp | base64
Mitigation:
1. Manual Fix (Pre-Patch):
// Override createTempFile() in SystemHelper.java File tempFile = Files.createTempFile(prefix, suffix).toFile(); tempFile.setReadable(false, false); // Restrict to owner
2. System Hardening:
chmod 750 /tmp/fess- && chown fess:admin /tmp/fess-
Detection:
1. Audit Logging:
auditctl -w /tmp -p war -k fess_tempfiles
2. YARA Rule for Suspicious Reads:
rule fess_tempfile_access {
strings: $ = "fess-..tmp"
condition: open and read and not uid == 0
}
Patch Verification:
jar xvf fess.jar | grep -A5 createTempFile Confirm permission checks
References:
- Fess GitHub Issue XYZ
- CWE-377: Insecure Temporary File
Analytics: Predicted exploitation spikes in shared cloud environments. Monitor /tmp access patterns post-patch.
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
