CVE-2013-2070 in nginx
Summary
by MITRE
http/modules/ngx_http_proxy_module.c in nginx 1.1.4 through 1.2.8 and 1.3.0 through 1.4.0, when proxy_pass is used with untrusted HTTP servers, allows remote attackers to cause a denial of service (crash) and obtain sensitive information from worker process memory via a crafted proxy response, a similar vulnerability to CVE-2013-2028.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability identified as CVE-2013-2070 represents a critical security flaw within the nginx web server software affecting versions 1.1.4 through 1.2.8 and 1.3.0 through 1.4.0. This issue specifically impacts the ngx_http_proxy_module component which handles proxy functionality when nginx acts as a reverse proxy server. The vulnerability arises from improper handling of crafted HTTP responses from upstream servers, creating a pathway for remote attackers to exploit the system through carefully constructed malicious responses.
The technical implementation flaw exists in how nginx processes proxy responses within the http/modules/ngx_http_proxy_module.c file. When nginx is configured with proxy_pass directives and communicates with untrusted HTTP servers, the software fails to properly validate or sanitize incoming response data. This inadequate input validation allows attackers to craft specific HTTP responses that trigger memory corruption within the nginx worker processes. The vulnerability operates by exploiting memory access patterns that occur during response processing, leading to potential crashes or memory leaks that expose sensitive data from the worker process memory space.
The operational impact of this vulnerability extends beyond simple denial of service conditions to include information disclosure risks that could compromise system security. Remote attackers can leverage this vulnerability to cause nginx worker processes to crash, resulting in service disruption and potential denial of service for legitimate users. More critically, the flaw enables information leakage from worker process memory, potentially exposing sensitive data such as session tokens, user credentials, or other confidential information that may be present in the memory segments of the affected processes. This dual nature of the vulnerability makes it particularly dangerous as it combines availability and confidentiality risks.
This vulnerability aligns with CWE-125, which describes "Out-of-bounds Read" conditions that can lead to information disclosure and system instability. The flaw also relates to the ATT&CK technique T1499.004, "Toggle Windows Event Log," and T1566.002, "Phishing with Malicious Attachment," as it can be exploited through malicious proxy responses that may be delivered via phishing campaigns or compromised upstream servers. The vulnerability demonstrates the importance of proper input validation and memory management in web server software, particularly when handling untrusted upstream responses.
The recommended mitigation strategies involve immediate upgrading to nginx versions that have addressed this vulnerability, specifically versions 1.4.1 and later where the proxy module has been patched to properly validate incoming responses. Organizations should also implement network segmentation and access controls to limit exposure to untrusted upstream servers, while monitoring for suspicious proxy traffic patterns. Additionally, implementing proper input validation at the application level and using intrusion detection systems to identify potential exploitation attempts can provide additional layers of protection against this class of vulnerability.