Embedthis GoAhead Remote Code Execution Vulnerability

Exploited · KEV 2021-12-10Metasploit moduleCVE-2017-17562CWE-20

Exploited since 2021-12-10. No WAF vendor names it yet. Our CRS test: not blocked.

Edge rules

0/8

Our test

Not blocked

CVSS

8.1

EPSS

97.1% Top 0.1%

Posts, 14d

Published

2017-12-12

Embedthis GoAhead before 3.6.5 allows remote code execution if CGI is enabled and a CGI program is dynamically linked. This is a result of initializing the environment of forked CGI scripts using untrusted HTTP request parameters in the cgiHandler function in cgi.c. When combined with the glibc dynamic linker, this behaviour can be abused for remote code execution using special parameter names such as LD_PRELOAD. An attacker can POST their shared object payload in the body of the request, and reference it using /proc/self/fd/0.

Edge coverage

Claimed by vendors

CloudflareBefore feed historyOlder than its feedWe measured: passed AWSBefore feed historyOlder than its feedWe measured: passed Microsoft AzureNo public claimNot named Google CloudBefore feed historyOlder than its feedWe measured: passed FastlyBefore feed historyOlder than its feed F5Before feed historyOlder than its feed AkamaiNo public sourceNo public changelog OWASP CRSBefore feed historyOlder than its feed

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Ask about CVE-2017-17562: who's covered, what to patch first, how vendors compare. I cite sources and won't help with attacks.

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Severity, decoded

CVSS 3.1

8.1High

High · 8.1 / 10

Exploitable over the network under specific conditions, with no privileges and no user interaction, leading to full loss of confidentiality, integrity and availability.

Over the internetNo login neededNo user actionHard to pull offFull compromise

How the score is built8 metrics

Attack vectorAn attacker can reach it over the internet; no access to your network needed.
Network
Attack complexityThe attack only works when conditions outside the attacker's control line up.
High
Privileges requiredNo account or login is needed.
None
User interactionNo one has to click or open anything; the attack works on its own.
None
ScopeThe damage stays within the vulnerable component.
Unchanged
Confidentiality impactAn attacker can read all data the affected component holds, or the most sensitive parts of it.
High
Integrity impactAn attacker can change any data or files the affected component protects.
High
Availability impactAn attacker can take the component down completely or keep it from serving anyone.
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA's assessmentSSVC, from the CVE record

ExploitationActive

Attackers are exploiting this in the wild.

AutomatableNo

At least one step needs hands-on work, which slows mass attacks.

Technical impactTotal

A successful attack gives full control over the affected software or all of its data.

Public exploits

4 found

1 Metasploit2 Exploit-DB1 Scanner template0 GitHub PoCs

MetasploitGoAhead Web Server LD_PRELOAD Arbitrary Module Load2017-12-18 · exploit · rank Excellent · has check
Exploit-DBGoAhead Web Server 2.5 < 3.6.5 - HTTPd 'LD_PRELOAD' Arbitrary Module Load (Metasploit)2018-01-24 · remote · multiple · verified
Exploit-DBGoAhead Web Server 2.5 < 3.6.5 - HTTPd 'LD_PRELOAD' Remote Code Execution2017-12-18 · remote · linux · verified
NucleiCVE-2017-17562.yamldetection template, replayed in our lab

Links are to third-party code: never run it outside an isolated lab.

Timeline

2017-12-12
CVE published
CVE List
2017-12-18
Metasploit module published
GoAhead Web Server LD_PRELOAD Arbitrary Module Load
2017-12-18
Exploit published on Exploit-DB
GoAhead Web Server 2.5 < 3.6.5 - HTTPd 'LD_PRELOAD' Remote Code Execution
2021-12-10
Added to CISA KEV
Confirmed exploitation in the wild
2026-11-02
Our test: OWASP Core Rule Set let it through
paranoia level 1, anomaly threshold 5, default CRS settings
2026-11-02
Our test: OWASP Core Rule Set let it through
paranoia level 2, anomaly threshold 5, default CRS settings