CVE-2021-40438
mod_proxy SSRF
Exploited in the wild. In CISA KEV since 2021‑12‑01. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
Multiple vulnerabilities were identified in the Apache HTTP Server software. These include NULL Pointer Dereferencing, Out-of-bounds Write and Server-Side Request Forgery related vulnerabilities. Siemens has released updates for several affected products and recommends to update to the latest versions. Siemens recommends specific countermeasures for products where updates are not, or not yet available.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Listed as exploited in the wild since 2021-12-01.
US federal agencies must remediate by 2021-12-15.
Known use in ransomware campaigns.
Apply updates per vendor instructions.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
100% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
14 events over 1785 days, from the signal feeds we watch.
- Patch availablerecord updated
- Patch availablerecord updated
- Patch availablerecord updated
- OpenVAS check added
- Nuclei check added
- Patch availablerecord updated
Affected products
- Red Hat Enterprise LinuxOperating Systems / linux-distro
- Red Hat Software CollectionsOperating Systems / linux-distro
- JBoss Core ServicesOperating Systems / linux-distro
- enterprise linux for arm 64Operating Systems / linux-distro
- enterprise linux for arm 64 eusOperating Systems / linux-distro
- enterprise linux for ibm z systemsOperating Systems / linux-distro
- enterprise linux for ibm z systems eusOperating Systems / linux-distro
- enterprise linux for ibm z systems eus s390xOperating Systems / linux-distro
And 28 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Scored 9.0 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- Command and ControlT1090Proxyhigh confidence
- Initial AccessT1190Exploit Public-Facing Applicationmedium confidence
Sources
References in the record
- cert-portal.siemens.com/productcert/csaf/ssa-685781.json
- cert-portal.siemens.com/productcert/txt/ssa-685781.txt
- cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf
And 49 more references. See all after sign-in
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