Bug 2002816 (CVE-2021-40528)
| Summary: | CVE-2021-40528 libgcrypt: ElGamal implementation allows plaintext recovery | ||
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| Product: | [Other] Security Response | Reporter: | Guilherme de Almeida Suckevicz <gsuckevi> |
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
| Status: | CLOSED ERRATA | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | bdettelb, caswilli, cfergeau, crypto-team, erik-fedora, fjansen, jjelen, kaycoth, marcandre.lureau, perobins, psegedy, rh-spice-bugs, rjones, ssorce, tcarlin, tcullum, tm, vkumar, vmugicag |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: |
A flaw was found in libgcrypt's ElGamal implementation, where it allows plain text recovery. During the interaction between two cryptographic libraries, a certain combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP. The highest threat from this vulnerability is to confidentiality.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2022-07-01 01:23:37 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 2002818, 2002819, 2018524, 2018525, 2018526, 2019492 | ||
| Bug Blocks: | 2002820 | ||
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Description
Guilherme de Almeida Suckevicz
2021-09-09 19:17:52 UTC
Created libgcrypt tracking bugs for this issue: Affects: fedora-all [bug 2002818] Created mingw-libgcrypt tracking bugs for this issue: Affects: fedora-all [bug 2002819] Heya, my reading of the paper in [1] suggests it is about CVE-2021-33560 which was already fixed in libgcrypt 1.8.8. The part 2 [2] discus the side channel attack, but references the same commit as a fix. Can you clarify what is here expected to be fixed in libgcrypt, when it has separate CVE number? [1] https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 [2] https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 [3] https://github.com/gpg/libgcrypt/commit/632d80ef3 Todd, I did not see any question in your last comment so I am removing the needinfo. Just found out this CVE was discussed in the upstream issue handling this: https://dev.gnupg.org/T5328#149606 They claim that this new CVE is about the side-channel attacks and upstream do not consider it as a vulnerability for various reasons. But I would love if you could get some clarification of the CVE page. It is very unclear, not mentioning the fix, upstream issue, anything, just the 1.9.4 version [2]. The CVE-2021-33560 was fixed also in 1.8.8 and in 1.9.3 (which is not correct either -- it is mentioned in the NEWS, but the patch is only in 1.9.4) [3]. I will close the Fedora bug as all the updates are already in stable. [1] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-40528 [2] https://dev.gnupg.org/source/libgcrypt/browse/master/NEWS;libgcrypt-1.9.4$6 [3] https://dev.gnupg.org/source/libgcrypt/browse/master/NEWS;libgcrypt-1.8.8$14 In reply to comment #5: > Todd, I did not see any question in your last comment so I am removing the > needinfo. > > Just found out this CVE was discussed in the upstream issue handling this: > > https://dev.gnupg.org/T5328#149606 > > They claim that this new CVE is about the side-channel attacks and upstream > do not consider it as a vulnerability for various reasons. > > But I would love if you could get some clarification of the CVE page. It is > very unclear, not mentioning the fix, upstream issue, anything, just the > 1.9.4 version [2]. The CVE-2021-33560 was fixed also in 1.8.8 and in 1.9.3 > (which is not correct either -- it is mentioned in the NEWS, but the patch > is only in 1.9.4) [3]. I'd be happy to check, but I do not have a clear communication stream with upstream at the moment. If we can get ahold of gniibe, that would be helpful. I've tried to register for an account there but am in a moderator queue for approval. This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2022:5311 https://access.redhat.com/errata/RHSA-2022:5311 This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2021-40528 |