CVE-2017-9103 – CVE-2017-9103 is a memory corruption vulnerabil... (How to Fix)

Q: What is the severity of CVE-2017-9103?

CVE-2017-9103 has a CVSS score of 9.8 (CRITICAL). CVE-2017-9103 is a memory corruption vulnerability in adns DNS resolver library where improper validation in pap_mailbox822 function allows using uninitialized stack values. This can lead to crashes, memory leaks, excessive memory allocation, or potential buffer overflows. Only applications making non-raw queries for SOA or RP records are affected.

📋 TL;DR

CVE-2017-9103 is a memory corruption vulnerability in adns DNS resolver library where improper validation in pap_mailbox822 function allows using uninitialized stack values. This can lead to crashes, memory leaks, excessive memory allocation, or potential buffer overflows. Only applications making non-raw queries for SOA or RP records are affected.

💻 Affected Systems

Products:

adns DNS resolver library

Versions: All versions before 1.5.2

Operating Systems: Linux, Unix-like systems

Default Config Vulnerable: ⚠️ Yes

Notes: Only vulnerable when applications use adns for non-raw SOA or RP record queries

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, though this would require specific memory layout conditions

🟠

Likely Case

Denial of service through application crashes or memory exhaustion

🟢

If Mitigated

Limited impact with proper input validation and memory protections

🌐 Internet-Facing: MEDIUM - Requires specific query types and affected application configuration

🏢 Internal Only: LOW - Typically DNS resolvers are internet-facing services

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires specific conditions and memory layout, making reliable exploitation challenging

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 1.5.2 and later

Vendor Advisory: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git

Restart Required: Yes

Instructions:

1. Download adns 1.5.2 or later from official repository. 2. Compile and install the updated version. 3. Restart any services using adns library.

🔧 Temporary Workarounds

Disable SOA/RP queries

all

Configure applications to avoid making non-raw SOA or RP record queries

Use alternative DNS resolver

linux

Replace adns with a different DNS resolver library that is not vulnerable

🧯 If You Can't Patch

Implement strict input validation for DNS queries in applications
Use memory protection mechanisms like ASLR and stack canaries

🔍 How to Verify

Check if Vulnerable:

Check adns version: adns version should show version number. Versions before 1.5.2 are vulnerable.

Check Version:

adns version 2>&1 | grep -i version || dpkg -l | grep adns || rpm -qa | grep adns

Verify Fix Applied:

Verify installed adns version is 1.5.2 or later using 'adns version' or package manager query

📡 Detection & Monitoring

Log Indicators:

Application crashes related to DNS resolution
Memory allocation errors in DNS-related processes

Network Indicators:

Unusual volume of SOA or RP DNS queries
DNS query patterns targeting vulnerable applications

SIEM Query:

source="application_logs" AND ("adns" OR "DNS resolution") AND ("crash" OR "segmentation fault" OR "memory allocation")

📊 Metadata

CVE ID: CVE-2017-9103

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-119

Published: June 18, 2020

Last Updated: November 21, 2024

🔗 References

http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00037.html Mailing List,Third Party Advisory
http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git Third Party Advisory
http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git%3Ba=blob%3Bf=changelog
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TRVHN3GGVNQWAOL3PWC5FLAV7HUESLZR/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UGFZ4SPV6KFQK6ZNUZFB5Y32OYFOM5YJ/
https://www.chiark.greenend.org.uk/pipermail/adns-announce/2020/000004.html Release Notes,Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00037.html Mailing List,Third Party Advisory
http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git Third Party Advisory
http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git%3Ba=blob%3Bf=changelog
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TRVHN3GGVNQWAOL3PWC5FLAV7HUESLZR/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UGFZ4SPV6KFQK6ZNUZFB5Y32OYFOM5YJ/
https://www.chiark.greenend.org.uk/pipermail/adns-announce/2020/000004.html Release Notes,Third Party Advisory

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