CVE-2020-15934: Privilege Escalation in FortiClientLinux
Platform
fortinet
Component
forticlientlinux-vcm-engine
Fixed in
6.4.1
6.2.8
6.2.5
6.0.9
6.0.7
CVE-2020-15934 describes a privilege escalation vulnerability within the VCM engine of FortiClient for Linux. This flaw allows a local attacker to elevate their privileges to root by exploiting the engine's handling of scripts. The vulnerability impacts versions 6.0.0 through 6.4.0 of FortiClientLinux, and a patch is available in version 6.4.1.
Impact and Attack Scenarios
Successful exploitation of CVE-2020-15934 grants an attacker root access to the affected system. This allows them to execute arbitrary commands, install malware, modify system configurations, and potentially compromise sensitive data. The attack vector requires local access to the machine, meaning an attacker must already have some foothold on the system. The blast radius is limited to the individual machine, but the impact of root access is severe, enabling complete control over the compromised host. This vulnerability shares similarities with other privilege escalation exploits that leverage flawed script execution handling.
Exploitation Context
CVE-2020-15934 was published on December 19, 2024. There is no indication of active exploitation campaigns or KEV listing at the time of writing. Public proof-of-concept exploits are not widely available, suggesting a relatively low probability of immediate widespread exploitation, but the ease of exploitation once a PoC is available warrants attention.
Threat Intelligence
Exploit Status
EPSS
0.07% (20% percentile)
CISA SSVC
CVSS Vector
What do these metrics mean?
- Attack Vector
- Adjacent — requires network proximity: same LAN, Bluetooth, or local wireless segment. Not internet-exposed.
- Attack Complexity
- Low — no special conditions required. Attacker can exploit reliably without depending on rare configurations or timing.
- Privileges Required
- None — unauthenticated. No login or credentials needed to exploit.
- User Interaction
- None — attack is automatic and silent. Victim does nothing: no click, no file open.
- Scope
- Unchanged — impact is limited to the vulnerable component itself.
- Confidentiality
- High — complete confidentiality loss. Attacker can read all data: credentials, keys, personal data.
- Integrity
- High — attacker can write, modify, or delete any data: databases, config files, or code.
- Availability
- High — complete crash or resource exhaustion. Full denial of service.
Affected Software
Weakness Classification (CWE)
Timeline
- Reserved
- Published
- Modified
- EPSS updated
Mitigation and Workarounds
The primary mitigation for CVE-2020-15934 is to upgrade FortiClientLinux to version 6.4.1 or later, which contains the fix. If immediate upgrading is not possible, consider restricting script execution permissions within the VCM engine. While a direct WAF rule is unlikely to be effective, monitoring for unusual process creation events related to the VCM engine can provide early detection. After upgrading, confirm the fix by attempting to execute a malicious script within the VCM engine and verifying that it fails to escalate privileges.
How to fix
Actualice FortiClient para Linux a una versión posterior a 6.4.0. Si no es posible actualizar, considere deshabilitar el motor VCM hasta que se pueda realizar la actualización. Consulte el advisory de Fortinet para obtener más detalles e instrucciones específicas.
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Frequently asked questions
What is CVE-2020-15934 — Privilege Escalation in FortiClientLinux?
CVE-2020-15934 is a privilege escalation vulnerability in FortiClientLinux VCM engine versions 6.0.0–6.4.0, allowing local attackers to gain root access.
Am I affected by CVE-2020-15934 in FortiClientLinux?
You are affected if you are running FortiClientLinux VCM engine versions 6.0.0 through 6.4.0. Upgrade to 6.4.1 or later to mitigate the risk.
How do I fix CVE-2020-15934 in FortiClientLinux?
Upgrade FortiClientLinux to version 6.4.1 or later. Consider restricting script execution permissions as a temporary workaround.
Is CVE-2020-15934 being actively exploited?
There is currently no evidence of active exploitation, but the vulnerability's ease of exploitation warrants vigilance.
Where can I find the official FortiClient advisory for CVE-2020-15934?
Refer to the Fortinet security advisory for detailed information and updates: [https://www.fortinet.com/security/advisories/vcm-engine-privilege-escalation]
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