Path traversal in request_uri variable
CVE-2021-43557

7.5HIGH

Key Information:

Vendor
Apache
Status
Apache Apisix
Vendor
CVE Published:
22 November 2021

Badges

👾 Exploit Exists🟡 Public PoC🟣 EPSS 47%

Summary

The uri-block plugin in Apache APISIX before 2.10.2 uses $request_uri without verification. The $request_uri is the full original request URI without normalization. This makes it possible to construct a URI to bypass the block list on some occasions. For instance, when the block list contains "^/internal/", a URI like //internal/ can be used to bypass it. Some other plugins also have the same issue. And it may affect the developer's custom plugin.

Affected Version(s)

Apache APISIX 1.5

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

k8s-CVE-2021-43557-poc
Created by xvnpw

References

https://lists.apache.org/thread/18jyd458ptocr31rnkjs71w4h...
x_refsource_MISC
http://www.openwall.com/lists/oss-security/2021/11/22/1
mailing-listx_refsource_MLIST
http://www.openwall.com/lists/oss-security/2021/11/22/2
mailing-listx_refsource_MLIST

EPSS Score

47% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.