SynopsisThe remote SUSE host is missing one or more security updates.
DescriptionThe remote SUSE Linux SLES11 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2020:14440-1 advisory.
- A flaw was found in grub2, prior to version 2.06. An attacker may use the GRUB 2 flaw to hijack and tamper the GRUB verification process. This flaw also allows the bypass of Secure Boot protections. In order to load an untrusted or modified kernel, an attacker would first need to establish access to the system such as gaining physical access, obtain the ability to alter a pxe-boot network, or have remote access to a networked system with root access. With this access, an attacker could then craft a string to cause a buffer overflow by injecting a malicious payload that leads to arbitrary code execution within GRUB. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (CVE-2020-10713)
- In grub2 versions before 2.06 the grub memory allocator doesn't check for possible arithmetic overflows on the requested allocation size. This leads the function to return invalid memory allocations which can be further used to cause possible integrity, confidentiality and availability impacts during the boot process. (CVE-2020-14308)
- There's an issue with grub2 in all versions before 2.06 when handling squashfs filesystems containing a symbolic link with name length of UINT32 bytes in size. The name size leads to an arithmetic overflow leading to a zero-size allocation further causing a heap-based buffer overflow with attacker controlled data. (CVE-2020-14309)
- There is an issue on grub2 before version 2.06 at function read_section_as_string(). It expects a font name to be at max UINT32_MAX - 1 length in bytes but it doesn't verify it before proceed with buffer allocation to read the value from the font value. An attacker may leverage that by crafting a malicious font file which has a name with UINT32_MAX, leading to read_section_as_string() to an arithmetic overflow, zero-sized allocation and further heap-based buffer overflow. (CVE-2020-14310)
- There is an issue with grub2 before version 2.06 while handling symlink on ext filesystems. A filesystem containing a symbolic link with an inode size of UINT32_MAX causes an arithmetic overflow leading to a zero-sized memory allocation with subsequent heap-based buffer overflow. (CVE-2020-14311)
- GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing, leading to arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and prior versions. (CVE-2020-15706)
- Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux component of GRUB2, as shipped in Debian, Red Hat, and Ubuntu (the functionality is not included in GRUB2 upstream), leading to a heap-based buffer overflow. These could be triggered by an extremely large number of arguments to the initrd command on 32-bit architectures, or a crafted filesystem with very large files on any architecture. An attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. This issue affects GRUB2 version 2.04 and prior versions. (CVE-2020-15707)
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
SolutionUpdate the affected grub2-x86_64-efi and / or grub2-x86_64-xen packages.
File Name: suse_SU-2020-14440-1.nasl
Supported Sensors: Nessus Agent
Temporal Vector: E:U/RL:OF/RC:C
Temporal Vector: E:U/RL:O/RC:C
CPE: p-cpe:/a:novell:suse_linux:grub2-x86_64-efi, p-cpe:/a:novell:suse_linux:grub2-x86_64-xen, cpe:/o:novell:suse_linux:11
Required KB Items: Host/local_checks_enabled, Host/cpu, Host/SuSE/release, Host/SuSE/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 7/29/2020
Vulnerability Publication Date: 7/29/2020