Red Hat Bugzilla – Bug 1559241
CVE-2018-8769 elfutils: buffer over-read in ebldynamictagname.c:ebl_dynamic_tag_name() allows for denial of service
Last modified: 2018-04-09 17:08:24 EDT
elfutils between commits 88f3d2daa107b09fdba376a82bce7ed534c93645 and 92581d7eb483cb039e60112b0a03a04c2ffa4df4 is vulnerable to a buffer over-read in the ebldynamictagname.c:ebl_dynamic_tag_name() function. An attacker could exploit this by supplying a crafted ELF file to display wrong data or potentially cause a crash in eu-readelf and eu-elflint binaries, depending on how programs are compiled. Upstream Issue: https://sourceware.org/bugzilla/show_bug.cgi?id=22976 Upstream Patch: https://sourceware.org/ml/elfutils-devel/2018-q1/msg00078.html
Created elfutils tracking bugs for this issue: Affects: fedora-all [bug 1559243]
Note that this is only used by eu-readelf and eu-elflint, it isn't exposed through any library. It isn't in upstream 0.170, but can though a backport of upstream commit: commit 88f3d2daa107b09fdba376a82bce7ed534c93645 Author: Mark Wielaard <mark@klomp.org> Date: Sat Feb 17 00:23:19 2018 +0100 libelf: Sync elf.h from glibc. Signed-off-by: Mark Wielaard <mark@klomp.org> Which is part of elfutils-0.170-elf_sync.patch which was added in Fedora in 0.170-9.
ISTM the CVSS score overstates the severity of this bug. I cannot think of a way in which confidentiality or availability is harmed by this, so 3.3=low seems to be more accurate. https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N Given that a fix is already in upstream elfutils, any objections to CLOSED/NEXTRELEASE for the fedora BZ?
I lowered the CVSSv3 score. Only Availability is affected, because you could make the program crash in case ebl_dynamic_tag_name returns a pointer to unmapped memory. It could also print other strings or values found in the process memory, but there is no way for an attacker to extract those strings, so I didn't put C:L.
Correction to previous comment: depending on how the programs gets compiled, the ebl_dynamic_tag_name function could either return a valid or an invalid pointer. In the first case you would just see a wrong string when displaying ELF info, in the second case you would get a crash. Thus I:L, A:L in the CVSSv3 score.
Statement: This issue did not affect the versions of elfutils as shipped with Red Hat Enterprise Linux 5, 6, and 7 as they did not include the vulnerable commit. This issue did not affect the versions of elfutils as shipped with Red Hat Developer Toolset 6 and 7 as they did not include the vulnerable commit.