Httpproxy — CraftedSignal Threat Feedhttps://feed.craftedsignal.io/tags/httpproxy/Trending threats, MITRE ATT&CK coverage, and detection metadata — refreshed continuously.Hugoenhello@craftedsignal.iohello@craftedsignal.ioSat, 26 Oct 2024 18:22:34 +0000OpenCanary HTTPPROXY Login Attempt Detectionhttps://feed.craftedsignal.io/briefs/2024-10-opencanary-httpproxy/Sat, 26 Oct 2024 18:22:34 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-10-opencanary-httpproxy/Detection of attempted HTTP proxy use on an OpenCanary node, indicating potential reconnaissance or lateral movement by an attacker attempting to proxy another page.This threat brief focuses on detecting malicious attempts to use an OpenCanary node as an HTTP proxy. OpenCanary is a low-interaction honeypot designed to detect intruders on a network. An attacker attempting to use an OpenCanary node as an HTTP proxy is a strong indicator of reconnaissance or lateral movement, as they are attempting to route their traffic through the honeypot. This activity is logged by OpenCanary and can be detected with appropriate monitoring. The default configuration of OpenCanary includes an HTTPPROXY service that listens for proxy requests. Defenders should monitor OpenCanary logs for event ID 7001, which indicates an attempted HTTP proxy login.

Attack Chain

  1. Attacker gains initial access to a network (e.g., through phishing or exploiting a vulnerability).
  2. Attacker performs network reconnaissance to identify potential targets, including the OpenCanary node.
  3. Attacker attempts to configure their system or tools to use the OpenCanary node as an HTTP proxy.
  4. The attacker sends HTTP requests through the configured proxy, attempting to reach other systems on the network.
  5. OpenCanary logs the attempted proxy connection with event ID 7001.
  6. The defender detects the suspicious HTTP proxy attempt in the OpenCanary logs.

Impact

A successful HTTP proxy attempt indicates that an attacker is actively exploring the network and attempting to move laterally. This could lead to further compromise of sensitive systems and data exfiltration. While the OpenCanary node itself is a honeypot and not a production asset, the detection of proxy attempts signals a breach and ongoing malicious activity within the network.

Recommendation

  • Deploy the provided Sigma rule OpenCanary HTTPPROXY Login Attempt to your SIEM and tune for your environment to detect unauthorized proxy attempts on OpenCanary nodes.
  • Investigate any alerts generated by the Sigma rule to determine the source and target of the attempted proxy connection.
  • Review OpenCanary configuration to ensure that the HTTPPROXY service is properly configured and secured.
  • Implement network segmentation to limit the impact of potential lateral movement by attackers.
]]>highadvisoryopencanaryhoneypothttpproxylateral-movementContour HTTPProxy Lua Code Injection via Cookie Path Rewritehttps://feed.craftedsignal.io/briefs/2024-01-09-contour-lua-injection/Tue, 09 Jan 2024 12:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-01-09-contour-lua-injection/Contour's Cookie Rewriting feature is vulnerable to Lua code injection; an attacker with RBAC permissions to create or modify HTTPProxy resources can craft a malicious value in the `spec.routes[].cookieRewritePolicies[].pathRewrite.value` or `spec.routes[].services[].cookieRewritePolicies[].pathRewrite.value` fields, resulting in arbitrary code execution in the Envoy proxy.Project Contour is susceptible to Lua code injection within its cookie rewriting functionality. The vulnerability arises from insufficient sanitization when user-controlled values are interpolated into Lua source code using Go’s text/template. This affects Contour versions 1.19.0 through 1.33.3. An attacker with the ability to create or modify HTTPProxy resources can inject arbitrary Lua code by crafting malicious values in spec.routes[].cookieRewritePolicies[].pathRewrite.value or spec.routes[].services[].cookieRewritePolicies[].pathRewrite.value. While the injected code executes within the attacker’s own route, the shared nature of the Envoy proxy allows for potential escalation of privileges, including reading Envoy’s xDS client credentials and causing denial of service for other tenants. This vulnerability is resolved in Contour versions v1.33.4, v1.32.5, and v1.31.6.

Attack Chain

  1. An attacker gains RBAC permissions to create or modify HTTPProxy resources within the Contour environment.
  2. The attacker crafts a malicious HTTPProxy resource containing a cookieRewritePolicies section.
  3. Within the cookieRewritePolicies, the attacker injects Lua code into the pathRewrite.value field.
  4. The attacker applies the crafted HTTPProxy resource, deploying the malicious configuration to Contour.
  5. Contour, using the Envoy proxy, processes the HTTPProxy resource, interpolating the attacker-controlled value into the Lua filter.
  6. When traffic is processed on the attacker’s route, the injected Lua code executes within the Envoy proxy.
  7. The injected Lua code attempts to read Envoy’s xDS client credentials from the filesystem.
  8. The attacker uses the obtained xDS client credentials to read all Contour xDS configuration, including TLS certificates and private keys of other tenants, or to cause a denial of service for other tenants sharing the Envoy instance.

Impact

A successful exploit allows attackers to execute arbitrary code within the Envoy proxy, potentially leading to credential theft and denial of service. Specifically, an attacker can steal TLS certificates and private keys of other tenants within the Contour environment. This could compromise sensitive data and disrupt services. If xDS credentials can be obtained, an attacker can then modify/exfiltrate service mesh configuration details.

Recommendation

  • Upgrade Contour to version v1.33.4, v1.32.5, or v1.31.6 to remediate the Lua code injection vulnerability as described in the overview.
  • Monitor HTTPProxy resource creation and modification events for suspicious patterns or unexpected values in the spec.routes[].cookieRewritePolicies[].pathRewrite.value and spec.routes[].services[].cookieRewritePolicies[].pathRewrite.value fields.
  • Implement RBAC least privilege principles to restrict access to creating and modifying HTTPProxy resources, mitigating the initial access vector required to exploit this vulnerability.
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