GHSA-955r-262c-33jc: Telnyx Telnyx Has Malicious Code Vulnerability

CRITICAL
CWE-506
Published
Advisory Summary

GHSA-955r-262c-33jc is a CRITICAL telnyx has malicious code vulnerability (CWE-506: Embedded Malicious Code) affecting Telnyx libraries in the PyPI ecosystem. The issue involves telnyx has malicious code in pypi versions 4.87.1 and 4.87.2. Remediation is available in the latest vendor maintenance releases.

GHSA-955r-262c-33jc at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-955r-262c-33jc
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification CWE-506: Embedded Malicious Code
Affected Product Telnyx
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix GHSA-955r-262c-33jc

To remediate this vulnerability, upgrade all affected Telnyx dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

telnyx fixed: Latest secure release
pip install telnyx>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

pip show telnyx

How to Check if You Are Affected

To determine whether your Python environment is affected by GHSA-955r-262c-33jc, inspect your installed packages using pip:

pip show telnyx

Analyze the terminal output to locate any version of Telnyx in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show telnyx command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-506: Embedded Malicious Code, where the product contains code that appears to be malicious in nature. In Telnyx, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## 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.service` | Linux | Persistence service | | `/tmp/.initd_state` | Linux/macOS | State tracking | | `%APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup\msbuild.exe` | Windows | Persistence binary | | `msbuild.exe.lock` | Windows | 12-hour cooldown lock | ### Exfiltration - Archive name: `tpcp.tar.gz` - HTTP header: `X-Filename: tpcp.tar.gz` - Encryption: AES-256-CBC + RSA-4096 OAEP ## Attribution This attack is attributed to **TeamPCP** with high confidence based on: - Identical RSA-4096 public key as the LiteLLM compromise (March 24, 2026) - `tpcp.tar.gz` archive naming convention (TeamPCP signature) - Identical AES-256-CBC + RSA OAEP encryption scheme - Same credential harvesting targets and techniques RSA Key Hash: - PEM SHA-256: `4eceb569b4330565b93058465beab0e6d5ea09cfba8e7f29d7be1b5a2abd958a` ## Resources - https://github.com/team-telnyx/telnyx-python/issues/235 - https://www.endorlabs.com/learn/teampcp-strikes-again-telnyx-compromised-three-days-after-litellm - https://ramimac.me/teampcp

GHSA-955r-262c-33jc Affected Telnyx Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
telnyx
PyPI
≥ 4.87.1
≤ 4.87.2

References

Frequently Asked Questions

What is GHSA-955r-262c-33jc?
GHSA-955r-262c-33jc is a security vulnerability in Telnyx involving Telnyx has malicious code in PyPI versions 4.87.1 and 4.87.2 under CWE-506: Embedded Malicious Code.
Which Telnyx versions are affected?
Affected versions include releases prior to current release patches across affected packages: telnyx.
What version fixes GHSA-955r-262c-33jc?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is telnyx affected?
Yes, telnyx is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What CWE is associated with GHSA-955r-262c-33jc?
GHSA-955r-262c-33jc is classified under CWE-506: Embedded Malicious Code (The product contains code that appears to be malicious in nature.).
How can I check PyPI dependencies for GHSA-955r-262c-33jc?
Run the dependency tree command: 'pip show telnyx'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-955r-262c-33jc",
  "modified" : "2026-03-30T19:15:30Z",
  "published" : "2026-03-30T19:15:30Z",
  "aliases" : [ ],
  "summary" : "Telnyx has malicious code in PyPI versions 4.87.1 and 4.87.2",
  "details" : "## Summary\n\nOn 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.\n\n## Exposure Window\n\n| Version | Published (UTC) | Quarantined (UTC) | Exposure |\n|---------|-----------------|-------------------|----------|\n| 4.87.1 (broken) | 2026-03-27 03:51 | 2026-03-27 10:13 | 6h 22m |\n| 4.87.2 (functional) | 2026-03-27 04:07 | 2026-03-27 10:13 | 6h 6m |\n\n\n**Both versions were quarantined by PyPI at 2026-03-27 10:13 UTC.**\n\n**Note:** Version 4.87.1 contained a typo that prevented the malware from executing. Only 4.87.2 was fully functional.\n\n## Who Is Affected\n\nYou may be affected if:\n- You installed or upgraded the `telnyx` Python package between 03:51 UTC and 10:13 UTC on March 27, 2026\n- You ran `pip install telnyx` without pinning a version and received 4.87.1 or 4.87.2\n- A dependency in your project pulled in `telnyx` as a transitive, unpinned dependency\n\nYou are NOT affected if:\n- You pinned to version 4.87.0 or earlier\n- You installed before March 27, 2026 and did not upgrade\n- You built from GitHub source (malicious code was never committed to the repository)\n\n## Attack Details\n\n### Root Cause\n\nThe 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.\n\n### Malicious Behavior\n\nThe malware is injected into `telnyx/_client.py` (74 additional lines) and executes on `import telnyx`:\n\n**Linux/macOS:**\n1. Spawns detached subprocess to survive parent exit\n2. Downloads payload hidden inside WAV audio file (steganography) from C2\n3. Harvests credentials: SSH keys, AWS/GCP/Azure creds, Kubernetes tokens, Docker configs, .env files, database credentials, crypto wallets\n4. If Kubernetes access found, deploys privileged pods to all nodes for lateral movement\n5. Encrypts with AES-256-CBC + RSA-4096, exfiltrates to C2\n\n**Windows:**\n1. Downloads binary hidden inside WAV file from C2\n2. Drops as `msbuild.exe` in Startup folder for persistence\n3. Executes with hidden window\n\n### Version Differences\n\n| Version | Status | Notes |\n|---------|--------|-------|\n| 4.87.1 | Broken | Typo: `Setup()` instead of `setup()` caused NameError |\n| 4.87.2 | Functional | Attacker uploaded 16 minutes later to fix their own casing error; full attack chain operational |\n\n## Verified Safe Version\n\n| Version | File | SHA-256 |\n|---------|------|--------|\n| **4.87.0** | `telnyx-4.87.0-py3-none-any.whl` | `5aeb8172c29ade224e6c2d166713f304596aa21e3dbfa5b6b2b028e6997f6bd2` |\n| **4.87.0** | `telnyx-4.87.0.tar.gz` | `3f093a85c313c2b779594f99fc07f453f1a7fd8785878d963688c531ff94d03a` |\n\n## Recommended Actions\n\n### 1. Check If You Are Affected\n\n```bash\n# Check installed version\npip show telnyx | grep Version\n\n# Check pip cache for telnyx versions\npip cache list telnyx 2>/dev/null\n\n# Check when telnyx was installed (modification time)\nls -la $(python -c \"import site; print(site.getsitepackages()[0])\")/telnyx* 2>/dev/null\n```\n\n### 2. Remove Compromised Versions\n\n```bash\npip uninstall telnyx\n```\n\n### 3. Rotate All Potentially Exposed Secrets\n\nIf there is any possibility that version 4.87.1 or 4.87.2 was installed in your environment, treat all accessible secrets as compromised:\n\n- SSH keys\n- AWS/GCP/Azure credentials\n- Kubernetes tokens and service accounts\n- Docker registry credentials\n- Database passwords\n- API keys in .env files\n- Telnyx API keys\n\n### 4. Check for Persistence (Linux/macOS)\n\n```bash\n# Check for malicious systemd service\nsystemctl --user status audiomon 2>/dev/null\nls -la ~/.config/audiomon/ 2>/dev/null\n\n# Check state file\nls -la /tmp/.initd_state 2>/dev/null\n```\n\n### 5. Check for Persistence (Windows)\n\n```powershell\n# Check Startup folder\nGet-ChildItem \"$env:APPDATA\\Microsoft\\Windows\\Start Menu\\Programs\\Startup\\msbuild.exe\"\n```\n\n### 6. Pin to Safe Version\n\n\n```bash\npip install telnyx==4.87.0\n```\n\nOr in requirements.txt:\n```\ntelnyx==4.87.0\n```\n\n## Indicators of Compromise\n\n### Malicious Package Hashes\n\n| File | SHA-256 |\n|------|--------|\n| `telnyx-4.87.1-py3-none-any.whl` | `7321caa303fe96ded0492c747d2f353c4f7d17185656fe292ab0a59e2bd0b8d9` |\n| `telnyx-4.87.2-py3-none-any.whl` | `cd08115806662469bbedec4b03f8427b97c8a4b3bc1442dc18b72b4e19395fe3` |\n\n### Network\n\n| IoC | Type |\n|-----|------|\n| `83.142.209.203` | C2 IP address |\n| `http://83.142.209.203:8080/ringtone.wav` | Payload endpoint (Linux/macOS) |\n| `http://83.142.209.203:8080/hangup.wav` | Payload endpoint (Windows) |\n| `http://83.142.209.203:8080/raw` | Persistence polling endpoint |\n\n### Filesystem\n\n| Path | Platform | Purpose |\n|------|----------|--------|\n| `~/.config/audiomon/audiomon.py` | Linux/macOS | Persistence implant |\n| `~/.config/systemd/user/audiomon.service` | Linux | Persistence service |\n| `/tmp/.initd_state` | Linux/macOS | State tracking |\n| `%APPDATA%\\Microsoft\\Windows\\Start Menu\\Programs\\Startup\\msbuild.exe` | Windows | Persistence binary |\n| `msbuild.exe.lock` | Windows | 12-hour cooldown lock |\n\n### Exfiltration\n\n- Archive name: `tpcp.tar.gz`\n- HTTP header: `X-Filename: tpcp.tar.gz`\n- Encryption: AES-256-CBC + RSA-4096 OAEP\n\n## Attribution\n\nThis attack is attributed to **TeamPCP** with high confidence based on:\n\n- Identical RSA-4096 public key as the LiteLLM compromise (March 24, 2026)\n- `tpcp.tar.gz` archive naming convention (TeamPCP signature)\n- Identical AES-256-CBC + RSA OAEP encryption scheme\n- Same credential harvesting targets and techniques\n\nRSA Key Hash:\n- PEM SHA-256: `4eceb569b4330565b93058465beab0e6d5ea09cfba8e7f29d7be1b5a2abd958a`\n\n## Resources\n\n- https://github.com/team-telnyx/telnyx-python/issues/235\n- https://www.endorlabs.com/learn/teampcp-strikes-again-telnyx-compromised-three-days-after-litellm\n- https://ramimac.me/teampcp",
  "severity" : [ ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "telnyx"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.87.1"
      }, {
        "last_affected" : "4.87.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/team-telnyx/telnyx-python/security/advisories/GHSA-955r-262c-33jc"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/team-telnyx/telnyx-python/issues/235"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/team-telnyx/telnyx-python"
  }, {
    "type" : "WEB",
    "url" : "https://ramimac.me/teampcp"
  }, {
    "type" : "WEB",
    "url" : "https://www.endorlabs.com/learn/teampcp-strikes-again-telnyx-compromised-three-days-after-litellm"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-506" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-30T19:15:30Z",
    "nvd_published_at" : null
  }
}