CVE-2024-30949
📋 TL;DR
A buffer overflow vulnerability in newlib's _gettimeofday function allows attackers to execute arbitrary code by exploiting improper time unit scaling. This affects embedded systems and IoT devices using newlib v4.3.0 for C library functionality. The vulnerability enables remote code execution with high impact.
💻 Affected Systems
- newlib
- Embedded systems using newlib
- IoT devices with newlib
- Cross-compiled applications using newlib
📦 What is this software?
Newlib by Newlib Project
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root-level arbitrary code execution, potentially leading to device takeover, data exfiltration, or lateral movement in embedded networks.
Likely Case
Remote code execution on vulnerable embedded devices, allowing attackers to install persistent malware, disrupt operations, or pivot to other systems.
If Mitigated
Limited impact if systems are isolated, have memory protection mechanisms, or lack network connectivity to the vulnerable component.
🎯 Exploit Status
Proof-of-concept available in references. Exploitation requires triggering the vulnerable function with malicious input, which may be accessible via network services or local applications.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in newlib commit 5f15d7c5817b07a6b18cbab17342c95cb7b42be4 and later
Vendor Advisory: https://sourceware.org/git/?p=newlib-cygwin.git;a=commit;h=5f15d7c5817b07a6b18cbab17342c95cb7b42be4
Restart Required: Yes
Instructions:
1. Update newlib to version after commit 5f15d7c5817b07a6b18cbab17342c95cb7b42be4. 2. Recompile all applications using newlib. 3. Redeploy updated firmware/images to affected devices. 4. Restart systems to load patched libraries.
🔧 Temporary Workarounds
Disable vulnerable time functions
allRemove or disable calls to _gettimeofday in applications if not essential
# Recompile applications with -DNO_GETTIMEOFDAY or similar flag
# Modify source code to avoid vulnerable function calls
Memory protection hardening
linuxEnable ASLR, stack canaries, and non-executable memory where supported
# For embedded Linux: echo 2 > /proc/sys/kernel/randomize_va_space
# Compile with -fstack-protector-all -D_FORTIFY_SOURCE=2
🧯 If You Can't Patch
- Network segmentation: Isolate affected embedded devices in restricted network zones
- Application control: Restrict which processes can call time-related functions
🔍 How to Verify
Check if Vulnerable:
Check newlib version: strings /path/to/libc.a | grep 'newlib' or examine build configuration for newlib v4.3.0Check Version:
grep 'newlib' /path/to/libc.a | head -1 or check build logs for newlib versionVerify Fix Applied:
Verify newlib commit includes 5f15d7c5817b07a6b18cbab17342c95cb7b42be4: git log --oneline | grep '5f15d7c'📡 Detection & Monitoring
Log Indicators:
- Abnormal process crashes in applications using time functions
- Unexpected child processes spawned from embedded applications
- Memory access violation logs in system logs
Network Indicators:
- Unusual network connections from embedded devices
- Unexpected outbound traffic from IoT devices
- Protocol anomalies in device communications
SIEM Query:
process_name:("app_using_newlib") AND (event_type:"crash" OR event_type:"memory_violation")