Vulnerabilities > CVE-2019-18183 - OS Command Injection vulnerability in multiple products
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Summary
pacman before 5.2 is vulnerable to arbitrary command injection in lib/libalpm/sync.c in the apply_deltas() function. This can be exploited when unsigned databases are used. To exploit the vulnerability, the user must enable the non-default delta feature and retrieve an attacker-controlled crafted database and delta file.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Command Line Execution through SQL Injection An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
- Command Delimiters An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or a blacklist input validation, as opposed to whitelist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or blacklist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on.
- Exploiting Multiple Input Interpretation Layers An attacker supplies the target software with input data that contains sequences of special characters designed to bypass input validation logic. This exploit relies on the target making multiples passes over the input data and processing a "layer" of special characters with each pass. In this manner, the attacker can disguise input that would otherwise be rejected as invalid by concealing it with layers of special/escape characters that are stripped off by subsequent processing steps. The goal is to first discover cases where the input validation layer executes before one or more parsing layers. That is, user input may go through the following logic in an application: In such cases, the attacker will need to provide input that will pass through the input validator, but after passing through parser2, will be converted into something that the input validator was supposed to stop.
- Argument Injection An attacker changes the behavior or state of a targeted application through injecting data or command syntax through the targets use of non-validated and non-filtered arguments of exposed services or methods.
- OS Command Injection In this type of an attack, an adversary injects operating system commands into existing application functions. An application that uses untrusted input to build command strings is vulnerable. An adversary can leverage OS command injection in an application to elevate privileges, execute arbitrary commands and compromise the underlying operating system.
Nessus
NASL family Fedora Local Security Checks NASL id FEDORA_2020-096FBCC91F.NASL description Update to latest version. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-04-16 modified 2020-04-10 plugin id 135368 published 2020-04-10 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135368 title Fedora 30 : pacman (2020-096fbcc91f) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Fedora Security Advisory FEDORA-2020-096fbcc91f. # include("compat.inc"); if (description) { script_id(135368); script_version("1.2"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/04/14"); script_cve_id("CVE-2019-18182", "CVE-2019-18183"); script_xref(name:"FEDORA", value:"2020-096fbcc91f"); script_name(english:"Fedora 30 : pacman (2020-096fbcc91f)"); script_summary(english:"Checks rpm output for the updated package."); script_set_attribute( attribute:"synopsis", value:"The remote Fedora host is missing a security update." ); script_set_attribute( attribute:"description", value: "Update to latest version. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues." ); script_set_attribute( attribute:"see_also", value:"https://bodhi.fedoraproject.org/updates/FEDORA-2020-096fbcc91f" ); script_set_attribute( attribute:"solution", value:"Update the affected pacman package." ); script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P"); script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C"); script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"); script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C"); script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:pacman"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:30"); script_set_attribute(attribute:"vuln_publication_date", value:"2020/02/24"); script_set_attribute(attribute:"patch_publication_date", value:"2020/04/09"); script_set_attribute(attribute:"plugin_publication_date", value:"2020/04/10"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof."); script_family(english:"Fedora Local Security Checks"); script_dependencies("ssh_get_info.nasl"); script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list"); exit(0); } include("audit.inc"); include("global_settings.inc"); include("rpm.inc"); if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED); release = get_kb_item("Host/RedHat/release"); if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora"); os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release); if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora"); os_ver = os_ver[1]; if (! preg(pattern:"^30([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 30", "Fedora " + os_ver); if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu); flag = 0; if (rpm_check(release:"FC30", reference:"pacman-5.2.1-2.fc30")) flag++; if (flag) { security_report_v4( port : 0, severity : SECURITY_WARNING, extra : rpm_report_get() ); exit(0); } else { tested = pkg_tests_get(); if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested); else audit(AUDIT_PACKAGE_NOT_INSTALLED, "pacman"); }
NASL family Fedora Local Security Checks NASL id FEDORA_2020-781D0B2EFE.NASL description Update to latest version. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-04-16 modified 2020-04-10 plugin id 135371 published 2020-04-10 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135371 title Fedora 31 : pacman (2020-781d0b2efe)
References
- https://git.archlinux.org/pacman.git/commit/?id=c0e9be7973be6c81b22fde91516fb8991e7bb07b
- https://git.archlinux.org/pacman.git/commit/?id=c0e9be7973be6c81b22fde91516fb8991e7bb07b
- https://git.archlinux.org/pacman.git/tree/lib/libalpm/sync.c?h=v5.1.3#n767
- https://git.archlinux.org/pacman.git/tree/lib/libalpm/sync.c?h=v5.1.3#n767
- https://github.com/alpinelinux/alpine-secdb/blob/master/v3.11/community.yaml
- https://github.com/alpinelinux/alpine-secdb/blob/master/v3.11/community.yaml
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2TTUXXUW5OCOASIRMJK4RHEPLEA33Y6C/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2TTUXXUW5OCOASIRMJK4RHEPLEA33Y6C/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K53C45EDWBU3UCN3IRIGR5EZUNWXS7BW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K53C45EDWBU3UCN3IRIGR5EZUNWXS7BW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KIDJ4XKBZRRVRFFGKUA3ZU6NFIP5JUG3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KIDJ4XKBZRRVRFFGKUA3ZU6NFIP5JUG3/