CVE-2021-40438— mod_proxy SSRF
Quick assessment
Affected
Apache Software Foundation Apache HTTP Server
Exploitation
Confirmed exploitation in the wild; remediate immediately
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Apache HTTP Server是美国阿帕奇（Apache）基金会的一款开源网页服务器。该服务器具有快速、可靠且可通过简单的API进行扩充的特点。 Apache HTTP Server存在代码问题漏洞，该漏洞是由于系统对用户的输入没有进行严格的过滤导致，攻击者可以构造恶意数据对目标服务器进行SSRF攻击。该漏洞可做为攻击目标服务器内网的跳板，以此对服务器所在内网进行端口扫描、攻击运行在内网的应用程序、下载内网资源等。
Public Exploits 1
Nuclei · 1
CVE-2021-40438.yaml [template]
In-the-Wild Activity Observed
cisa_kev · confirmed
Possible ATT&CK Techniques 1 AI
T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | Apache HTTP Server 2.4≤ 2.4.48 |
affected |
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I. Basic Information for CVE-2021-40438
Vulnerability Information
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Vulnerability Title
mod_proxy SSRF
Source: CVE Program / CVE List V5
Vulnerability Description
A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
服务端请求伪造(SSRF)
Source: CVE Program / CVE List V5
Vulnerability Title
Apache HTTP Server 代码问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Apache HTTP Server是美国阿帕奇（Apache）基金会的一款开源网页服务器。该服务器具有快速、可靠且可通过简单的API进行扩充的特点。 Apache HTTP Server存在代码问题漏洞，该漏洞是由于系统对用户的输入没有进行严格的过滤导致，攻击者可以构造恶意数据对目标服务器进行SSRF攻击。该漏洞可做为攻击目标服务器内网的跳板，以此对服务器所在内网进行端口扫描、攻击运行在内网的应用程序、下载内网资源等。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Shenlong Deep Dive — AI Deep Analysis
10-question deep dive: root cause, exploitation, mitigation, urgency. Read summary free, full version requires login.
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | Apache HTTP Server 2.4 ~ 2.4.48 | - |
|
II. Public POCs for CVE-2021-40438
| # | POC Description | Source Link | Shenlong Link |
|---|---|---|---|
| 1 | None | https://github.com/xiaojiangxl/CVE-2021-40438 | POC Details |
| 2 | CVE-2021-40438 exploit PoC with Docker setup. | https://github.com/sixpacksecurity/CVE-2021-40438 | POC Details |
| 3 | None | https://github.com/BabyTeam1024/CVE-2021-40438 | POC Details |
| 4 | Dockerized Proof-of-Concept of CVE-2021-40438 in Apache 2.4.48. | https://github.com/ericmann/apache-cve-poc | POC Details |
| 5 | Sigma-Rule-for-CVE-2021-40438-Attack-Attemp | https://github.com/pisut4152/Sigma-Rule-for-CVE-2021-40438-exploitation-attempt | POC Details |
| 6 | Apache forward request CVE | https://github.com/Kashkovsky/CVE-2021-40438 | POC Details |
| 7 | check CVE-2021-40438 | https://github.com/gassara-kys/CVE-2021-40438 | POC Details |
| 8 | CVE-2021-40438 Apache <= 2.4.48 SSRF exploit | https://github.com/sergiovks/CVE-2021-40438-Apache-2.4.48-SSRF-exploit | POC Details |
| 9 | Apache <= 2.4.48 Mod_Proxy - Server-Side Request Forgery | https://github.com/Cappricio-Securities/CVE-2021-40438 | POC Details |
| 10 | Check Point Security Gateways RCE via CVE-2021-40438 | https://github.com/element-security/check-point-gateways-rce | POC Details |
| 11 | Check Point Security Gateways RCE via CVE-2021-40438 | https://github.com/yakir2b/check-point-gateways-rce | POC Details |
| 12 | Apache 2.4.48 and below contain an issue where uri-path can cause mod_proxy to forward the request to an origin server chosen by the remote user. | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-40438.yaml | POC Details |
| 13 | None | https://github.com/Threekiii/Awesome-POC/blob/master/%E4%B8%AD%E9%97%B4%E4%BB%B6%E6%BC%8F%E6%B4%9E/Apache%20HTTP%20Server%202.4.48%20mod_proxy%20SSRF%E6%BC%8F%E6%B4%9E%20CVE-2021-40438.md | POC Details |
| 14 | None | https://github.com/chaitin/xray-plugins/blob/main/poc/manual/apache-httpd-cve-2021-40438-ssrf.yml | POC Details |
| 15 | https://github.com/vulhub/vulhub/blob/master/httpd/CVE-2021-40438/README.md | POC Details | |
| 16 | None | https://github.com/n0m-d/CVE-2021-40438-POC | POC Details |
AI-Generated POC
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Vendor Advisories for CVE-2021-40438 (8)
-
https://www.oracle.com/security-alerts/cpujan2022.html x_refsource_MISC
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https://www.oracle.com/security-alerts/cpuapr2022.html x_refsource_MISC
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https://security.netapp.com/advisory/ntap-20211008-0004/ x_refsource_CONFIRM
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https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf x_refsource_CONFIRM
-
-
🔗 Apache HTTPD: Multiple Vulnerabilities (GLSA 202208-20) — Gentoo security Read full article vendor-advisory x_refsource_GENTOO
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https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ vendor-advisory x_refsource_CISCO
Mailing List Discussions for CVE-2021-40438 (8)
-
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/ vendor-advisory x_refsource_FEDORA
-
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/ vendor-advisory x_refsource_FEDORA
-
https://lists.apache.org/thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37%40%3Cbugs.httpd.apache.org%3E mailing-list x_refsource_MLIST
-
Other References for CVE-2021-40438 (1)
-
https://www.tenable.com/security/tns-2021-17 x_refsource_CONFIRM
Same Patch Batch · Apache Software Foundation · 2021-09-16 · 6 CVEs total
| CVE-2021-41079 | Apache Tomcat DoS with unexpected TLS packet | |
| CVE-2021-39275 | ap_escape_quotes buffer overflow | |
| CVE-2021-39239 | XML External Entity (XXE) vulnerability | |
| CVE-2021-36160 | mod_proxy_uwsgi out of bound read | |
| CVE-2021-34798 | NULL pointer dereference in httpd core |
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-
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V. Comments for CVE-2021-40438
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