CVE-2020-10531
📋 TL;DR
This CVE describes an integer overflow leading to heap-based buffer overflow in ICU's UnicodeString::doAppend() function. Attackers can exploit this to execute arbitrary code or cause denial of service. Systems using ICU library versions through 66.1 in C/C++ applications are affected.
💻 Affected Systems
- International Components for Unicode (ICU)
- Chromium/Chrome
- Red Hat Enterprise Linux
- SUSE Linux
- Applications using ICU library
📦 What is this software?
Chrome by Google
Google Chrome is the world's most popular web browser, used by over 3 billion users globally across Windows, macOS, Linux, Android, and iOS platforms. As a Chromium-based browser developed by Google, Chrome dominates the browser market with approximately 65% market share, making it a critical compon...
Learn more about Chrome →Fedora by Fedoraproject
Fedora by Fedoraproject
Fedora by Fedoraproject
International Components For Unicode by Icu Project
View all CVEs affecting International Components For Unicode →
Leap by Opensuse
Node.js by Nodejs
Node.js by Nodejs
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crash causing denial of service, potentially leading to data corruption.
If Mitigated
Limited impact with proper memory protections (ASLR, DEP) and sandboxing in place.
🎯 Exploit Status
Exploitation requires triggering the integer overflow with specific Unicode string manipulations. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: ICU 66.2 and later
Vendor Advisory: https://access.redhat.com/errata/RHSA-2020:0738
Restart Required: Yes
Instructions:
1. Update ICU library to version 66.2 or later. 2. For Linux distributions, use package manager: 'sudo yum update icu' (RHEL) or 'sudo apt-get update && sudo apt-get upgrade icu' (Debian/Ubuntu). 3. Rebuild and redeploy applications using ICU. 4. Restart affected services.
🔧 Temporary Workarounds
Memory Protection Hardening
linuxEnable ASLR, DEP, and other memory protection mechanisms to reduce exploit success.
echo 2 > /proc/sys/kernel/randomize_va_space
sysctl -w kernel.exec-shield=1
Application Sandboxing
linuxRun vulnerable applications in containers or sandboxes to limit impact.
docker run --security-opt=no-new-privileges -d your_app
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable systems
- Deploy web application firewall (WAF) with buffer overflow protection rules
🔍 How to Verify
Check if Vulnerable:
Check ICU version: 'icu-config --version' or 'dpkg -l | grep icu' or 'rpm -qa | grep icu'. If version is 66.1 or earlier, system is vulnerable.Check Version:
icu-config --version 2>/dev/null || dpkg -l | grep icu 2>/dev/null || rpm -qa | grep icu 2>/dev/nullVerify Fix Applied:
Verify ICU version is 66.2 or later using same commands. Test application functionality with Unicode input.📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory corruption errors in application logs
- Unusual Unicode string processing patterns
Network Indicators:
- Unusual Unicode payloads in HTTP requests
- Large Unicode strings sent to applications
SIEM Query:
source="application.logs" AND ("segmentation fault" OR "buffer overflow" OR "heap corruption")🔗 References
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00004.html
- https://access.redhat.com/errata/RHSA-2020:0738
- https://bugs.chromium.org/p/chromium/issues/detail?id=1044570
- https://chromereleases.googleblog.com/2020/02/stable-channel-update-for-desktop_24.html
- https://chromium.googlesource.com/chromium/deps/icu/+/9f4020916eb1f28f3666f018fdcbe6c9a37f0e08
- https://github.com/unicode-org/icu/commit/b7d08bc04a4296982fcef8b6b8a354a9e4e7afca
- https://github.com/unicode-org/icu/pull/971
- https://lists.debian.org/debian-lts-announce/2020/03/msg00024.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4OOYAMJVLLCLXDTHW3V5UXNULZBBK4O6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6IOHSO6BUKC6I66J5PZOMAGFVJ66ZS57/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X3B5RWJQD5LA45MYLLR55KZJOJ5NVZGP/
- https://security.gentoo.org/glsa/202003-15
- https://unicode-org.atlassian.net/browse/ICU-20958
- https://usn.ubuntu.com/4305-1/
- https://www.debian.org/security/2020/dsa-4646
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00004.html
- https://access.redhat.com/errata/RHSA-2020:0738
- https://bugs.chromium.org/p/chromium/issues/detail?id=1044570
- https://chromereleases.googleblog.com/2020/02/stable-channel-update-for-desktop_24.html
- https://chromium.googlesource.com/chromium/deps/icu/+/9f4020916eb1f28f3666f018fdcbe6c9a37f0e08
- https://github.com/unicode-org/icu/commit/b7d08bc04a4296982fcef8b6b8a354a9e4e7afca
- https://github.com/unicode-org/icu/pull/971
- https://lists.debian.org/debian-lts-announce/2020/03/msg00024.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4OOYAMJVLLCLXDTHW3V5UXNULZBBK4O6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6IOHSO6BUKC6I66J5PZOMAGFVJ66ZS57/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X3B5RWJQD5LA45MYLLR55KZJOJ5NVZGP/
- https://security.gentoo.org/glsa/202003-15
- https://unicode-org.atlassian.net/browse/ICU-20958
- https://usn.ubuntu.com/4305-1/
- https://www.debian.org/security/2020/dsa-4646
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujan2021.html
