CVE-2017-17562
Embedthis GoAhead Remote Code Execution Vulnerability
Description
CVE-2017-17562 is a high-severity remote code execution vulnerability in Embedthis GoAhead, a widely used embedded web server. GoAhead versions before 3.6.5 allow remote code execution when CGI is enabled and a CGI program is dynamically linked. The vulnerability arises from the cgiHandler function initializing the environment of forked CGI scripts using untrusted HTTP request parameters, which when combined with the glibc dynamic linker, enables attackers to abuse special parameter names such as LD_PRELOAD for arbitrary code execution. CISA has confirmed active exploitation of this Embedthis GoAhead vulnerability by adding it to the Known Exploited Vulnerabilities catalog. With an EPSS score of 94.34% (99.96th percentile), CVE-2017-17562 has a near-certain probability of exploitation.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| embedthis | goahead | < 3.6.5 |
| oracle | integrated lights out manager | 3.0; 4.0 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html(Patch, Third Party Advisory)
- http://www.securitytracker.com/id/1040702(Broken Link, Third Party Advisory, VDB Entry)
- https://github.com/elttam/advisories/tree/master/CVE-2017-17562(Broken Link, Third Party Advisory)
- https://github.com/embedthis/goahead/commit/6f786c123196eb622625a920d54048629a7caa74(Broken Link, Patch, Third Party Advisory)
- https://github.com/embedthis/goahead/issues/249(Broken Link, Issue Tracking, Third Party Advisory)
- https://www.elttam.com.au/blog/goahead/(Broken Link, Exploit, Patch, Third Party Advisory)
- https://www.exploit-db.com/exploits/43360/(Exploit, Third Party Advisory, VDB Entry)
- https://www.exploit-db.com/exploits/43877/(Exploit, Third Party Advisory, VDB Entry)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-17562(US Government Resource)
Weakness Type
CWE-94: Improper Control of Generation of Code ('Code Injection')
The NVD does not assign a specific CWE to CVE-2017-17562, but the vulnerability fundamentally involves code injection through environment variable manipulation. In Embedthis GoAhead, untrusted HTTP request parameters are passed directly into the CGI process environment, allowing attackers to inject the LD_PRELOAD variable to load arbitrary shared objects and execute malicious code on the target system.
Learn more: CWE-94 — Improper Control of Generation of Code
Impact Analysis
CVE-2017-17562 carries a CVSS 3.1 score of 8.1 (HIGH), representing a serious threat to organizations using Embedthis GoAhead web servers with CGI enabled. The vulnerability is remotely exploitable over the network without any authentication or user interaction required, though exploitation complexity is rated high due to the requirement that CGI must be enabled and programs must be dynamically linked. Confidentiality (High): successful exploitation grants attackers full read access to the server and its data. Integrity (High): attackers can modify any data or configurations on the compromised system. Availability (High): complete denial of service is possible. The EPSS score of 94.34% places this vulnerability in the 99.96th percentile, indicating near-certain exploitation activity. The scope remains unchanged, meaning the impact is confined to the vulnerable GoAhead server component, but given that GoAhead is commonly deployed in IoT devices and embedded systems, compromised devices can serve as pivot points for broader network attacks.
Exploit Maturity
CVE-2017-17562 has a mature exploit landscape with multiple publicly available exploits. Public exploit code is available via Exploit-DB (43360) and Exploit-DB (43877), along with a detailed technical writeup from elttam that includes exploit methodology. CISA has confirmed active exploitation in the wild through the KEV catalog, with a remediation deadline of 2022-06-10. The EPSS score of 94.34% (99.96th percentile) indicates near-certain exploitation activity, reflecting the widespread availability of exploit code and the prevalence of vulnerable GoAhead instances in IoT and embedded environments.
Remediation
- Apply vendor patches immediately as mandated by CISA KEV: Apply updates per vendor instructions. Upgrade Embedthis GoAhead to version 3.6.5 or later, which addresses the environment variable injection vulnerability in the CGI handler.
- For Oracle Integrated Lights Out Manager users, apply the patches referenced in Oracle's Critical Patch Update Advisory from April 2018 for affected versions 3.0 and 4.0.
- If immediate patching is not possible, disable CGI functionality in GoAhead as an interim mitigation. Alternatively, ensure CGI programs are statically linked rather than dynamically linked, which prevents the LD_PRELOAD attack vector.
- Implement network segmentation to isolate devices running GoAhead web servers, particularly IoT and embedded devices, from critical network segments. Apply strict firewall rules to limit access to the web server interface.
- Monitor network traffic and server logs for suspicious POST requests containing environment variable names (LD_PRELOAD, LD_LIBRARY_PATH) in HTTP parameters, which are indicators of attempted exploitation.
Technical Details
CVE-2017-17562 exploits a flaw in the cgiHandler function within cgi.c of Embedthis GoAhead before version 3.6.5. The vulnerable code initializes the environment of forked CGI scripts using untrusted HTTP request parameters without filtering dangerous environment variables. An attacker can exploit this by sending a specially crafted HTTP POST request containing parameters with names corresponding to glibc dynamic linker variables, most notably LD_PRELOAD. By POSTing a shared object payload in the request body and referencing it via /proc/self/fd/0, the attacker forces the dynamically linked CGI program to load and execute the malicious shared library. The CVSS vector (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) reflects that while the attack is network-based and requires no privileges, the complexity is high because CGI must be enabled with dynamically linked programs, which is not the default configuration in all deployments.
Frequently Asked Questions
Is CVE-2017-17562 being actively exploited?
Yes. CVE-2017-17562 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. The EPSS score of 94.34% (99.96th percentile) indicates near-certain exploitation probability. Multiple public exploits are readily available.
What products are affected by CVE-2017-17562?
CVE-2017-17562 affects Embedthis GoAhead versions prior to 3.6.5. Additionally, Oracle Integrated Lights Out Manager versions 3.0 and 4.0, which incorporate GoAhead, are also affected.
How do I fix CVE-2017-17562?
Upgrade Embedthis GoAhead to version 3.6.5 or later. If immediate patching is not possible, disable CGI functionality or ensure CGI programs are statically linked. For Oracle ILOM, apply patches from Oracle's April 2018 Critical Patch Update.
How severe is CVE-2017-17562?
CVE-2017-17562 has a CVSS 3.1 score of 8.1 (HIGH). Combined with the near-certain exploitation probability (EPSS 94.34%), confirmed active exploitation, and multiple public exploits, this vulnerability demands immediate remediation action.
Need Help With Vulnerability Management?
Our security experts can help you prioritize and remediate vulnerabilities effectively.