mirror of
https://github.com/HackTricks-wiki/hacktricks.git
synced 2025-10-10 18:36:50 +00:00
Merge pull request #1264 from HackTricks-wiki/research_update_src_network-services-pentesting_pentesting-631-internet-printing-protocol-ipp_20250809_012555
Research Update Enhanced src/network-services-pentesting/pen...
This commit is contained in:
SirBroccoli
GitHub
commit
9f02ef0154
@ -2,27 +2,104 @@
|
||||
|
||||
{{#include ../banners/hacktricks-training.md}}
|
||||
|
||||
The **Internet Printing Protocol (IPP)**, as specified in **RFC2910** and **RFC2911**, serves as a foundation for printing over the internet. Its capability to be extended is showcased by developments like **IPP Everywhere**, which aims to standardize mobile and cloud printing, and the introduction of extensions for **3D printing**.
|
||||
The **Internet Printing Protocol (IPP)**, as specified in **RFC 2910** and **RFC 2911**, is the de-facto standard for network printing. It sits on top of **HTTP/1.1** (either clear-text or TLS) and exposes a rich API for creating print jobs, querying printer capabilities and managing queues. Modern extensions such as **IPP Everywhere** even allow driver-less printing from mobile and cloud environments, while the same packet format has been reused for 3-D printers.
|
||||
|
||||
Leveraging the **HTTP** protocol, IPP benefits from established security practices including **basic/digest authentication** and **SSL/TLS encryption**. Actions like submitting a print job or querying printer status are performed through **HTTP POST requests** directed at the IPP server, which operates on **port 631/tcp**.
|
||||
|
||||
A well-known implementation of IPP is **CUPS**, an open-source printing system prevalent across various Linux distributions and OS X. Despite its utility, IPP, akin to LPD, can be exploited to transmit malicious content through **PostScript** or **PJL files**, highlighting a potential security risk.
|
||||
Unfortunately, exposing port **631/tcp (and 631/udp for printer discovery)** often leads to serious security issues – both on traditional office printers and on any Linux/Unix host running **CUPS**.
|
||||
|
||||
---
|
||||
## Quick PoC – crafting raw IPP with Python
|
||||
```python
|
||||
# Example of sending an IPP request using Python
|
||||
import requests
|
||||
import struct, requests
|
||||
|
||||
url = "http://printer.example.com:631/ipp/print"
|
||||
headers = {"Content-Type": "application/ipp"}
|
||||
data = b"..." # IPP request data goes here
|
||||
# Minimal IPP Get-Printer-Attributes request (operation-id 0x000B)
|
||||
ipp = struct.pack(
|
||||
">IHHIHH", # version 2.0, operation-id, request-id
|
||||
0x0200, # 2.0
|
||||
0x000B, # Get-Printer-Attributes
|
||||
0x00000001, # request-id
|
||||
0x01, 0x47, # operation-attributes-tag, charset attr (skipped)
|
||||
) + b"\x03" # end-of-attributes
|
||||
|
||||
response = requests.post(url, headers=headers, data=data, verify=True)
|
||||
print(response.status_code)
|
||||
r = requests.post("http://printer:631/ipp/print", headers={"Content-Type":"application/ipp"}, data=ipp)
|
||||
print(r.status_code, r.content[:40])
|
||||
```
|
||||
---
|
||||
## Enumeration & Recon
|
||||
|
||||
If you want to learn more about [**hacking printers read this page**](http://hacking-printers.net/wiki/index.php/Main_Page).
|
||||
### 1. Nmap NSE
|
||||
```bash
|
||||
# run all CUPS/IPP scripts
|
||||
nmap -sV -p631 --script=cups* <target>
|
||||
# or only basic info
|
||||
nmap -p631 --script=cups-info,cups-queue-info <target>
|
||||
```
|
||||
The `cups-info` script extracts model, state and queue statistics while `cups-queue-info` enumerates pending jobs.
|
||||
|
||||
### 2. IPP utilities from CUPS
|
||||
* `ippfind` – multicast/UDP discovery (works against cups-browsed):
|
||||
```bash
|
||||
ippfind --timeout 3 --txt -v "@local and port=631" # list printers
|
||||
```
|
||||
* `ipptool` – arbitrary requests defined in a *.test* file:
|
||||
```bash
|
||||
ipptool -tv ipp://<IP>/ipp/print get-printer-attributes.test
|
||||
```
|
||||
The bundled *get-printer-attributes.test* file queries firmware version, supported document formats, etc.
|
||||
|
||||
### 3. Shodan / Censys dorks
|
||||
```bash
|
||||
shodan search 'product:"CUPS (IPP)" port:631'
|
||||
```
|
||||
More than **70 000** hosts were publicly exposing CUPS in April 2025 .
|
||||
|
||||
---
|
||||
## Recent Vulnerabilities (2023-2025)
|
||||
|
||||
| Year | CVE ID(s) | Affected component | Impact |
|
||||
|------|-----------|--------------------|--------|
|
||||
| 2025 | CVE-2023-50739 | Lexmark firmware (IPP parser) | Heap-overflow → RCE over Wi-Fi/LAN |
|
||||
| 2024 | CVE-2024-47076, 47175, 47176, 47177 | cups-browsed, libcupsfilters, libppd, cups-filters | Full unauthenticated RCE chain on any Linux desktop/server with CUPS browsing enabled |
|
||||
| 2024 | CVE-2024-35235 | cupsd 2.4.8- | Symlink trick → arbitrary **chmod 666** → privilege escalation |
|
||||
| 2023 | CVE-2023-0856 (Canon) + Pwn2Own | Stack-overflow in `sides` attribute → remote code execution |
|
||||
|
||||
### cups-browsed RCE chain (September 2024)
|
||||
1. `cups-browsed` listens on **UDP/631** for printer advertisements.
|
||||
2. An attacker sends a single spoofed packet pointing to a malicious IPP URL (CVE-2024-47176).
|
||||
3. `libcupsfilters` automatically fetches the remote **PPD** without validation (CVE-2024-47076 & 47175).
|
||||
4. A crafted PPD abuses the **foomatic-rip** filter to execute arbitrary shell commands whenever anything is printed (CVE-2024-47177).
|
||||
|
||||
Proof-of-concept code is public on the researcher’s blog and exploits require **no authentication**; network access to UDP/631 is enough.
|
||||
|
||||
#### Temporary mitigations
|
||||
```
|
||||
sudo systemctl stop cups-browsed
|
||||
sudo systemctl disable cups-browsed
|
||||
sudo ufw deny 631/udp # or equivalent firewall rule
|
||||
```
|
||||
Patches were released by major distributions in October 2024 – ensure **cups-filters ≥ 2.0.0**.
|
||||
|
||||
### cupsd symlink `Listen` misconfiguration (CVE-2024-35235)
|
||||
Placing a symbolic link in *cupsd.conf*’s `Listen` directive causes **cupds (root)** to `chmod 666` an attacker-chosen path, leading to writable system files and, on Ubuntu, code execution via a malicious PPD with `FoomaticRIPCommandLine` .
|
||||
|
||||
---
|
||||
## Offensive Techniques
|
||||
|
||||
* **Unauthenticated raw print job** – many printers accept `POST /ipp/print` without auth. A malicious **PostScript** payload can invoke shell commands (`system("/bin/nc ...")`) on high-end devices.
|
||||
* **Job Hijacking** – `Cancel-Job` followed by `Send-Document` lets an attacker replace someone else’s document before it is physically printed.
|
||||
* **SNMP → IPP combo** – default community `public` often leaks the internal queue name required in the IPP URL.
|
||||
|
||||
---
|
||||
## Defensive Best Practices
|
||||
1. Patch CUPS and printer firmware promptly; subscribe to vendor PSIRT feeds.
|
||||
2. Disable `cups-browsed` and UDP/631 unless zeroconf printing is required.
|
||||
3. Restrict TCP/631 to trusted subnets/VPN and enforce **TLS (ipps://)**.
|
||||
4. Require **Kerberos/Negotiate** or certificate auth instead of anonymous printing.
|
||||
5. Monitor logs: `/var/log/cups/error_log` with `LogLevel debug2` will show unsolid PPD downloads or suspicious filter invocations.
|
||||
6. In high-security networks, move printing to a hardened, isolated print server that proxies jobs to devices via USB only.
|
||||
|
||||
|
||||
|
||||
## References
|
||||
- Akamai – “Critical Linux RCE Vulnerability in CUPS — What We Know and How to Prepare”, April 2025.
|
||||
- Debian Security Tracker – CVE-2024-35235 details.
|
||||
{{#include ../banners/hacktricks-training.md}}
|
||||
|
||||
|
||||
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user