Executive Summary

The vulnerability in Net::Statsite::Client versions through 1.1.0 for Perl is due to improper sanitization of metric names and values, which allows metric injection attacks.

Specifically, newlines are not removed from metric names, and values are not sanitized for newlines or other protocol control characters such as colons or pipes. This enables attackers to inject malicious input that can forge additional metric lines or corrupt existing ones.

The issue arises because the send() method serializes metrics using a format where ':' and '|' act as field separators and '\n' as record separators, but the sanitization misses newline characters and does not sanitize values at all.

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Impact Analysis

This vulnerability can allow an attacker to perform injection attacks by inserting malicious metric data into the statsite protocol communication.

Such injections can lead to forged additional metric lines (cross-record injection) or corruption of existing metric records (within-record injection), potentially misleading monitoring systems or causing incorrect metric aggregation.

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Detection Guidance

This vulnerability involves injection of newlines and control characters into metric names and values sent via the Statsite/StatsD UDP protocol. Detection can focus on monitoring UDP traffic to the statsite server for suspicious metric payloads containing unexpected newline characters or protocol control characters such as colons (:) and pipes (|) within metric names or values.

You can use network packet capture tools like tcpdump or Wireshark to capture UDP packets on the port used by statsite (default is often 8125). For example, a tcpdump command to capture UDP traffic on port 8125 would be:

• tcpdump -i <interface> udp port 8125 -A

After capturing, inspect the payloads for metric lines containing unexpected newline characters or multiple metric lines injected in a single UDP packet.

Additionally, on the system running the vulnerable Net::Statsite::Client, you can audit logs or application output for malformed metric names or values containing control characters.

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Mitigation Strategies

To mitigate this vulnerability, you should update Net::Statsite::Client to a version that includes the patch which properly sanitizes metric names and values by removing newlines and control characters.

If an immediate upgrade is not possible, consider implementing input validation or sanitization on the client side to strip or escape newline characters and protocol separators (':', '|') from metric names and values before sending.

Also, monitor and restrict network access to the statsite UDP port to trusted sources only, reducing the risk of injection from untrusted clients.

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Compliance Impact

The vulnerability in Net::Statsite::Client allows metric injections due to improper sanitization of metric names and values, which could lead to injection attacks via the Statsite/StatsD UDP protocol.

However, there is no information provided in the available context or resources about how this vulnerability specifically impacts compliance with common standards and regulations such as GDPR or HIPAA.

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