CVE-2021-20204
📋 TL;DR
CVE-2021-20204 is a critical heap memory corruption vulnerability (use-after-free) in libgetdata v0.10.0 that allows attackers to execute arbitrary code or escalate privileges by processing malicious dirfile databases. This affects any software that uses libgetdata as a library, potentially compromising confidentiality, integrity, and availability. The vulnerability is particularly dangerous due to its high CVSS score of 9.8.
💻 Affected Systems
- libgetdata
- Any software using libgetdata library
📦 What is this software?
Fedora by Fedoraproject
Fedora by Fedoraproject
Fedora by Fedoraproject
Getdata by Getdata Project
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise through arbitrary code execution leading to privilege escalation, data exfiltration, and complete system control.
Likely Case
Application crash leading to denial of service, with potential for remote code execution if attackers can supply malicious dirfile databases.
If Mitigated
Limited impact through proper input validation and sandboxing, though memory corruption could still cause crashes.
🎯 Exploit Status
Exploitation requires crafting malicious dirfile databases, but no public proof-of-concept has been released. The use-after-free nature makes reliable exploitation non-trivial but possible for skilled attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: libgetdata version 0.10.1 or later
Vendor Advisory: https://bugzilla.redhat.com/show_bug.cgi?id=1956348
Restart Required: Yes
Instructions:
1. Update libgetdata to version 0.10.1 or later using your distribution's package manager. 2. Restart any services or applications using libgetdata. 3. For Red Hat/Fedora: 'sudo dnf update libgetdata'. 4. For Debian/Ubuntu: 'sudo apt update && sudo apt upgrade libgetdata'.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict validation of dirfile database inputs to reject potentially malicious files before processing.
Application Sandboxing
linuxRun applications using libgetdata in restricted environments with limited privileges to contain potential exploitation.
# Example using systemd: add 'ProtectSystem=strict' and 'PrivateTmp=true' to service unit
🧯 If You Can't Patch
- Isolate systems using libgetdata from untrusted networks and limit access to trusted sources only.
- Implement strict file integrity monitoring for dirfile databases and alert on unexpected modifications.
🔍 How to Verify
Check if Vulnerable:
Check libgetdata version: 'ldconfig -p | grep libgetdata' or 'dpkg -l | grep libgetdata' on Debian/Ubuntu, 'rpm -qa | grep libgetdata' on Red Hat/Fedora.Check Version:
pkg-config --modversion libgetdata || getdata --version 2>/dev/null || echo 'Check package manager'Verify Fix Applied:
Verify libgetdata version is 0.10.1 or later using version check commands and test with known safe dirfile databases.📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults when processing dirfile databases
- Unexpected memory access errors in application logs
- Abnormal process termination of services using libgetdata
Network Indicators:
- Unusual network connections originating from applications using libgetdata
- Unexpected outbound data transfers following dirfile processing
SIEM Query:
source="application_logs" ("segmentation fault" OR "SIGSEGV" OR "use-after-free") AND process="*libgetdata*"🔗 References
- https://bugzilla.redhat.com/show_bug.cgi?id=1956348
- https://lists.debian.org/debian-lts-announce/2021/05/msg00015.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/43JTGEMYMCTHD3LHFD7ENBNSWCNBCYEY/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GB7T7DW7XRPJOUE25ZE7GF244FPCHBWY/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OE23HBLIVKVPOQ5MVADWPOCFMREVF4QZ/
- https://bugzilla.redhat.com/show_bug.cgi?id=1956348
- https://lists.debian.org/debian-lts-announce/2021/05/msg00015.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/43JTGEMYMCTHD3LHFD7ENBNSWCNBCYEY/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GB7T7DW7XRPJOUE25ZE7GF244FPCHBWY/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OE23HBLIVKVPOQ5MVADWPOCFMREVF4QZ/
