Telnyx has malicious code in PyPI versions 4.87.1 and 4.87.2
Summary
On March 27, 2026, a threat actor used compromised PyPI credentials to publish malicious versions 4.87.1 and 4.87.2 of the telnyx Python package directly to PyPI. These versions contain credential-stealing malware and were not published through the legitimate GitHub release pipeline.
Exposure Window
| Version | Published (UTC) | Quarantined (UTC) | Exposure |
|---------|-----------------|-------------------|----------|
| 4.87.1 (broken) | 2026-03-27 03:51 | 2026-03-27 10:13 | 6h 22m |
| 4.87.2 (functional) | 2026-03-27 04:07 | 2026-03-27 10:13 | 6h 6m |
Both versions were quarantined by PyPI at 2026-03-27 10:13 UTC.
Note: Version 4.87.1 contained a typo that prevented the malware from executing. Only 4.87.2 was fully functional.
Who Is Affected
You may be affected if:
- You installed or upgraded the
telnyx Python package between 03:51 UTC and 10:13 UTC on March 27, 2026 - You ran
pip install telnyx without pinning a version and received 4.87.1 or 4.87.2 - A dependency in your project pulled in
telnyx as a transitive, unpinned dependency
You are NOT affected if:
- You pinned to version 4.87.0 or earlier
- You installed before March 27, 2026 and did not upgrade
- You built from GitHub source (malicious code was never committed to the repository)
Attack Details
Root Cause
The attacker obtained the PyPI API token and uploaded malicious packages directly to PyPI, bypassing the GitHub release pipeline entirely. No malicious commits exist in the GitHub repository.
Malicious Behavior
The malware is injected into telnyx/_client.py (74 additional lines) and executes on import telnyx:
Linux/macOS:
1. Spawns detached subprocess to survive parent exit
2. Downloads payload hidden inside WAV audio file (steganography) from C2
3. Harvests credentials: SSH keys, AWS/GCP/Azure creds, Kubernetes tokens, Docker configs, .env files, database credentials, crypto wallets
4. If Kubernetes access found, deploys privileged pods to all nodes for lateral movement
5. Encrypts with AES-256-CBC + RSA-4096, exfiltrates to C2
Windows:
1. Downloads binary hidden inside WAV file from C2
2. Drops as msbuild.exe in Startup folder for persistence
3. Executes with hidden window
Version Differences
| Version | Status | Notes |
|---------|--------|-------|
| 4.87.1 | Broken | Typo: Setup() instead of setup() caused NameError |
| 4.87.2 | Functional | Attacker uploaded 16 minutes later to fix their own casing error; full attack chain operational |
Verified Safe Version
| Version | File | SHA-256 |
|---------|------|--------|
| 4.87.0 | telnyx-4.87.0-py3-none-any.whl | 5aeb8172c29ade224e6c2d166713f304596aa21e3dbfa5b6b2b028e6997f6bd2 |
| 4.87.0 | telnyx-4.87.0.tar.gz | 3f093a85c313c2b779594f99fc07f453f1a7fd8785878d963688c531ff94d03a |
Recommended Actions
1. Check If You Are Affected
```bash
# Check installed version
pip show telnyx | grep Version
# Check pip cache for telnyx versions
pip cache list telnyx 2>/dev/null
# Check when telnyx was installed (modification time)
ls -la $(python -c "import site; print(site.getsitepackages()[0])")/telnyx* 2>/dev/null
```
2. Remove Compromised Versions
```bash
pip uninstall telnyx
```
3. Rotate All Potentially Exposed Secrets
If there is any possibility that version 4.87.1 or 4.87.2 was installed in your environment, treat all accessible secrets as compromised:
- SSH keys
- AWS/GCP/Azure credentials
- Kubernetes tokens and service accounts
- Docker registry credentials
- Database passwords
- API keys in .env files
- Telnyx API keys
4. Check for Persistence (Linux/macOS)
```bash
# Check for malicious systemd service
systemctl --user status audiomon 2>/dev/null
ls -la ~/.config/audiomon/ 2>/dev/null
# Check state file
ls -la /tmp/.initd_state 2>/dev/null
```
5. Check for Persistence (Windows)
```powershell
# Check Startup folder
Get-ChildItem "$env:APPDATA\Microsoft\Windows\Start Menu\Programs\Startup\msbuild.exe"
```
6. Pin to Safe Version
```bash
pip install telnyx==4.87.0
```
Or in requirements.txt:
```
telnyx==4.87.0
```
Indicators of Compromise
Malicious Package Hashes
| File | SHA-256 |
|------|--------|
| telnyx-4.87.1-py3-none-any.whl | 7321caa303fe96ded0492c747d2f353c4f7d17185656fe292ab0a59e2bd0b8d9 |
| telnyx-4.87.2-py3-none-any.whl | cd08115806662469bbedec4b03f8427b97c8a4b3bc1442dc18b72b4e19395fe3 |
Network
| IoC | Type |
|-----|------|
| 83.142.209.203 | C2 IP address |
| http://83.142.209.203:8080/ringtone.wav | Payload endpoint (Linux/macOS) |
| http://83.142.209.203:8080/hangup.wav | Payload endpoint (Windows) |
| http://83.142.209.203:8080/raw | Persistence polling endpoint |
Filesystem
| Path | Platform | Purpose |
|------|----------|--------|
| ~/.config/audiomon/audiomon.py | Linux/macOS | Persistence implant |
| `~/.config/systemd/user/audiomon.ser
