An issue was discovered in disable_priv_mode in shell.c in GNU Bash through 5.0 patch 11. By default, if Bash is run with its effective UID not equal to its real UID, it will drop privileges by setting its effective UID to its real UID. However, it does so incorrectly. On Linux and other systems that support "saved UID" functionality, the saved UID is not dropped. An attacker with command execution in the shell can use "enable -f" for runtime loading of a new builtin, which can be a shared object that calls setuid() and therefore regains privileges. However, binaries running with an effective UID of 0 are unaffected.

The remote Redhat Enterprise Linux 7 host has one or more packages installed that are affected by multiple vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - bash: when effective UID is not equal to its real UID the saved UID is not dropped (CVE-2019-18276)

  - A heap-based buffer overflow exists in GNU Bash before 4.3 when wide characters, not supported by the     current locale set in the LC_CTYPE environment variable, are printed through the echo built-in function. A     local attacker, who can provide data to print through the echo -e built-in function, may use this flaw     to crash a script or execute code with the privileges of the bash process. This occurs because ansicstr()     in lib/sh/strtrans.c mishandles u32cconv(). (CVE-2012-6711)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package is installed.

This plugin has been deprecated as it does not adhere to established standards for this style of check.

The remote Ubuntu 16.04 ESM / 18.04 LTS / 20.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-5380-1 advisory.

    It was discovered that Bash did not properly drop privileges when the binary had the setuid bit enabled.
    An attacker could possibly use this issue to escalate privileges.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote host is affected by the vulnerability described in GLSA-202105-34 (Bash: Privilege escalation)

    It was discovered that Bash incorrectly dropped privileges by setting       its effective UID to its real UID.
  Impact :

    A local attacker could possibly escalate privileges.
  Workaround :

    There is no known workaround at this time.

The remote Oracle Linux 8 host has packages installed that are affected by a vulnerability as referenced in the ELSA-2021-1679 advisory.

    [4.4.19-14]
    - Fix hang when limit for nproc is very high       Resolves: #1890888

    [4.4.19-13]
    - Correctly drop saved UID when effective UID is not equal to its real UID       Resolves: #1793943

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote CentOS Linux 8 host has packages installed that are affected by a vulnerability as referenced in the CESA-2021:1679 advisory.

  - bash: when effective UID is not equal to its real UID the saved UID is not dropped (CVE-2019-18276)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2021:1679 advisory.

    The bash packages provide Bash (Bourne-again shell), which is the default shell for Red Hat Enterprise     Linux.

    Security Fix(es):

    * bash: when effective UID is not equal to its real UID the saved UID is not dropped (CVE-2019-18276)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

    Additional Changes:

    For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.4 Release Notes     linked from the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

According to the version of the bash package installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  - An issue was discovered in disable_priv_mode in shell.c     in GNU Bash through 5.0 patch 11. By default, if Bash     is run with its effective UID not equal to its real     UID, it will drop privileges by setting its effective     UID to its real UID. However, it does so incorrectly.
    On Linux and other systems that support 'saved UID'     functionality, the saved UID is not dropped. An     attacker with command execution in the shell can use     'enable -f' for runtime loading of a new builtin, which     can be a shared object that calls setuid() and     therefore regains privileges. However, binaries running     with an effective UID of 0 are     unaffected.(CVE-2019-18276)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the version of the bash package installed, the EulerOS Virtualization installation on the remote host is affected by the following vulnerability :

  - An issue was discovered in disable_priv_mode in shell.c     in GNU Bash through 5.0 patch 11. By default, if Bash     is run with its effective UID not equal to its real     UID, it will drop privileges by setting its effective     UID to its real UID. However, it does so incorrectly.
    On Linux and other systems that support 'saved UID'     functionality, the saved UID is not dropped. An     attacker with command execution in the shell can use     'enable -f' for runtime loading of a new builtin, which     can be a shared object that calls setuid() and     therefore regains privileges. However, binaries running     with an effective UID of 0 are     unaffected.(CVE-2019-18276)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the version of the bash package installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerability :

  - An issue was discovered in disable_priv_mode in shell.c     in GNU Bash through 5.0 patch 11. By default, if Bash     is run with its effective UID not equal to its real     UID, it will drop privileges by setting its effective     UID to its real UID. However, it does so incorrectly.
    On Linux and other systems that support 'saved UID'     functionality, the saved UID is not dropped. An     attacker with command execution in the shell can use     'enable -f' for runtime loading of a new builtin, which     can be a shared object that calls setuid() and     therefore regains privileges. However, binaries running     with an effective UID of 0 are     unaffected.(CVE-2019-18276)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the version of the bash package installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerability :

  - A privilege escalation vulnerability was found in bash     in the way it dropped privileges when started with an     effective user id not equal to the real user id. Bash     may be vulnerable to this flaw if the setuid permission     is set and the owner of the bash program itself is a     non-root user. A local attacker could exploit this flaw     to escalate their privileges on the     system.(CVE-2019-18276)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the version of the bash packages installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  - An issue was discovered in disable_priv_mode in shell.c     in GNU Bash through 5.0 patch 11. By default, if Bash     is run with its effective UID not equal to its real     UID, it will drop privileges by setting its effective     UID to its real UID. However, it does so incorrectly.
    On Linux and other systems that support 'saved UID'     functionality, the saved UID is not dropped. An     attacker with command execution in the shell can use     'enable -f' for runtime loading of a new builtin, which     can be a shared object that calls setuid() and     therefore regains privileges. However, binaries running     with an effective UID of 0 are     unaffected.(CVE-2019-18276)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

An update of the bash package has been released.

ID	Name	Product	Family	Severity
198803	RHEL 7 : bash (Unpatched Vulnerability)	Nessus	Red Hat Local Security Checks	high
196146	RHEL 5 : bash (Unpatched Vulnerability) (deprecated)	Nessus	Red Hat Local Security Checks	high
196136	RHEL 6 : bash (Unpatched Vulnerability) (deprecated)	Nessus	Red Hat Local Security Checks	high
159982	Ubuntu 16.04 ESM / 18.04 LTS / 20.04 LTS : Bash vulnerability (USN-5380-1)	Nessus	Ubuntu Local Security Checks	high
157010	GLSA-202105-34 : Bash: Privilege escalation	Nessus	Gentoo Local Security Checks	high
149940	Oracle Linux 8 : bash (ELSA-2021-1679)	Nessus	Oracle Linux Local Security Checks	high
149781	CentOS 8 : bash (CESA-2021:1679)	Nessus	CentOS Local Security Checks	high
149652	RHEL 8 : bash (RHSA-2021:1679)	Nessus	Red Hat Local Security Checks	high
142298	EulerOS 2.0 SP2 : bash (EulerOS-SA-2020-2328)	Nessus	Huawei Local Security Checks	high
141731	EulerOS Virtualization 3.0.2.2 : bash (EulerOS-SA-2020-2218)	Nessus	Huawei Local Security Checks	high
140848	EulerOS 2.0 SP3 : bash (EulerOS-SA-2020-2081)	Nessus	Huawei Local Security Checks	high
137935	EulerOS Virtualization 3.0.6.0 : bash (EulerOS-SA-2020-1716)	Nessus	Huawei Local Security Checks	high
136263	EulerOS Virtualization for ARM 64 3.0.2.0 : bash (EulerOS-SA-2020-1560)	Nessus	Huawei Local Security Checks	high
135130	EulerOS Virtualization for ARM 64 3.0.6.0 : bash (EulerOS-SA-2020-1343)	Nessus	Huawei Local Security Checks	high
134845	EulerOS 2.0 SP5 : bash (EulerOS-SA-2020-1303)	Nessus	Huawei Local Security Checks	high
133974	EulerOS 2.0 SP8 : bash (EulerOS-SA-2020-1140)	Nessus	Huawei Local Security Checks	high
133812	Photon OS 1.0: Bash PHSA-2020-1.0-0277	Nessus	PhotonOS Local Security Checks	high
133806	Photon OS 3.0: Bash PHSA-2020-3.0-0057	Nessus	PhotonOS Local Security Checks	high
133803	Photon OS 2.0: Bash PHSA-2020-2.0-0208	Nessus	PhotonOS Local Security Checks	high

Detections

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CVE-2019-18276

critical

Tenable Plugins

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