CVE-2020-8597
📋 TL;DR
CVE-2020-8597 is a critical buffer overflow vulnerability in pppd (Point-to-Point Protocol daemon) that allows remote attackers to execute arbitrary code or cause denial of service. The vulnerability affects systems running pppd versions 2.4.2 through 2.4.8 with EAP authentication enabled. This primarily impacts Linux/Unix systems using PPP for network connections.
💻 Affected Systems
- ppp
- pppd
📦 What is this software?
Point To Point Protocol by Point To Point Protocol Project
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attacker gains full root privileges on affected system, leading to complete system compromise, data theft, and lateral movement.
Likely Case
Remote code execution with root privileges, allowing attackers to install malware, create backdoors, or disrupt network services.
If Mitigated
Denial of service through system crash if exploit fails or is blocked by security controls.
🎯 Exploit Status
Multiple public exploit proofs-of-concept exist. Exploitation is straightforward once network access to pppd service is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: ppp 2.4.9 and later
Vendor Advisory: https://access.redhat.com/errata/RHSA-2020:0630
Restart Required: Yes
Instructions:
1. Update ppp package to version 2.4.9 or later using your distribution's package manager. 2. For Red Hat/CentOS: 'yum update ppp'. 3. For Debian/Ubuntu: 'apt-get update && apt-get install ppp'. 4. Restart any services using pppd.
🔧 Temporary Workarounds
Disable EAP authentication
linuxRemove or disable EAP authentication in pppd configuration to prevent exploitation
Edit /etc/ppp/options or pppd configuration files and remove 'require-eap', 'refuse-eap', or similar EAP-related options
Network segmentation
linuxRestrict network access to pppd services using firewall rules
iptables -A INPUT -p tcp --dport [pppd-port] -j DROP
iptables -A INPUT -p udp --dport [pppd-port] -j DROP
🧯 If You Can't Patch
- Disable EAP authentication in all pppd configurations immediately
- Implement strict network access controls to limit exposure of pppd services
🔍 How to Verify
Check if Vulnerable:
Check pppd version with 'pppd --version' and verify if between 2.4.2-2.4.8. Check if EAP is enabled in configuration files.Check Version:
pppd --version 2>&1 | head -1Verify Fix Applied:
Verify pppd version is 2.4.9 or later with 'pppd --version'. Check that EAP options are removed from configuration.📡 Detection & Monitoring
Log Indicators:
- pppd crash logs in syslog
- Unexpected pppd process termination
- EAP authentication failures or anomalies
Network Indicators:
- Unexpected connections to pppd ports
- Malformed EAP packets in network traffic
SIEM Query:
source="syslog" AND (process="pppd" AND (event="segmentation fault" OR event="buffer overflow" OR event="crash"))🔗 References
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00006.html
- http://packetstormsecurity.com/files/156662/pppd-2.4.8-Buffer-Overflow.html
- http://packetstormsecurity.com/files/156802/pppd-2.4.8-Buffer-Overflow.html
- http://seclists.org/fulldisclosure/2020/Mar/6
- https://access.redhat.com/errata/RHSA-2020:0630
- https://access.redhat.com/errata/RHSA-2020:0631
- https://access.redhat.com/errata/RHSA-2020:0633
- https://access.redhat.com/errata/RHSA-2020:0634
- https://cert-portal.siemens.com/productcert/pdf/ssa-809841.pdf
- https://github.com/paulusmack/ppp/commit/8d7970b8f3db727fe798b65f3377fe6787575426
- https://kb.netgear.com/000061806/Security-Advisory-for-Unauthenticated-Remote-Buffer-Overflow-Attack-in-PPPD-on-WAC510-PSV-2020-0136
- https://lists.debian.org/debian-lts-announce/2020/02/msg00005.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UNJNHWOO4XF73M2W56ILZUY4JQG3JXIR/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YOFDAIOWSWPG732ASYUZNINMXDHY4APE/
- https://security.gentoo.org/glsa/202003-19
- https://security.netapp.com/advisory/ntap-20200313-0004/
- https://us-cert.cisa.gov/ics/advisories/icsa-20-224-04
- https://usn.ubuntu.com/4288-1/
- https://usn.ubuntu.com/4288-2/
- https://www.debian.org/security/2020/dsa-4632
- https://www.kb.cert.org/vuls/id/782301
- https://www.synology.com/security/advisory/Synology_SA_20_02
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00006.html
- http://packetstormsecurity.com/files/156662/pppd-2.4.8-Buffer-Overflow.html
- http://packetstormsecurity.com/files/156802/pppd-2.4.8-Buffer-Overflow.html
- http://seclists.org/fulldisclosure/2020/Mar/6
- https://access.redhat.com/errata/RHSA-2020:0630
- https://access.redhat.com/errata/RHSA-2020:0631
- https://access.redhat.com/errata/RHSA-2020:0633
- https://access.redhat.com/errata/RHSA-2020:0634
- https://cert-portal.siemens.com/productcert/pdf/ssa-809841.pdf
- https://github.com/paulusmack/ppp/commit/8d7970b8f3db727fe798b65f3377fe6787575426
- https://kb.netgear.com/000061806/Security-Advisory-for-Unauthenticated-Remote-Buffer-Overflow-Attack-in-PPPD-on-WAC510-PSV-2020-0136
- https://lists.debian.org/debian-lts-announce/2020/02/msg00005.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UNJNHWOO4XF73M2W56ILZUY4JQG3JXIR/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YOFDAIOWSWPG732ASYUZNINMXDHY4APE/
- https://security.gentoo.org/glsa/202003-19
- https://security.netapp.com/advisory/ntap-20200313-0004/
- https://us-cert.cisa.gov/ics/advisories/icsa-20-224-04
- https://usn.ubuntu.com/4288-1/
- https://usn.ubuntu.com/4288-2/
- https://www.debian.org/security/2020/dsa-4632
- https://www.kb.cert.org/vuls/id/782301
- https://www.synology.com/security/advisory/Synology_SA_20_02
