Vulnerability in github.com/google/go-tpm (CVE-2020-8918)
Summary
Vulnerability in github.com/google/go-tpm (CVE-2020-8918). Confidential information can be exposed externally. Exploitable via usageAuth. Mitigation: upgrade to 0.3.0 or later.
Original description
The description as published by the source.
Impact
TPM 2.0 users are unaffected by this issue.
An adversary eavesdropping on the TPM 1.2 transport path can calculate usageAuth for a key created with CreateWrapKey, even though this value is encrypted as part of the TPM 1.2 command protocol.
The TPM 1.2 CreateWrapKey command accepts two secrets: usageAuth and migrationAuth. The ADIP protocol (TPM 1.2 specification, part 1, section 13.4) calls for these values to be encrypted with two different XOR keys. Due to a bug in go-tpm prior to version 0.3.0, both usageAuth and migrationAuth are encrypted with the same XOR keystream. This allows an adversary to XOR encUsageAuth and encMigrationAuth together to calculate usageAuth ^ encMigrationAuth. Since migrationAuth is moot for all keys created with go-tpm's CreateWrapKey (since all keys created with this function are marked non-migratable), an adversary may guess or know (from code/binary inspection) that migrationAuth is all 0x00 bytes or some other fixed value. Such an adversary can then calculate usageAuth and use this value later to improperly use the created key, unbeknownst to the creator of the key.
Patches
Fixed in go-tpm version 0.3.0.
Workarounds
- TPM 2.0 users: No workaround needed. This issue only affects TPM 1.2 users.
- TPM 1.2 users: Call CreateWrapKey with a random 20-byte value for
migrationAuth, even th…
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2020-8918 has been found in github.com/google/go-tpm.
Attackers can target a specific entry point like usageAuth over the network to misuse the product.
Confidential information can be exposed externally.
What to do: upgrade github.com/google/go-tpm to 0.3.0 or later.
If unsure, ask your IT team or search "github.com/google/go-tpm CVE-2020-8918" on the vendor's site.
CVE-2020-8918 (github.com/google/go-tpm) — CWE-665
Attack vector: local / no user interaction
Attack surface: usageAuth / migrationAuth / encUsageAuth / encMigrationAuth
Patched: 0.3.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-665) exists in github.com/google/go-tpm. Attackers reach the vulnerable code path via usageAuth.
Check the vendor advisory for the affected versions of github.com/google/go-tpm. Attack surface: usageAuth / migrationAuth / encUsageAuth / encMigrationAuth.
Severity: ?. Confidential information can be exposed externally.
Update to 0.3.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/google/go-tpm' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/google/go-tpm' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/google/go-tpmを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/google/go-tpm to 0.3.0ステージング環境で 0.3.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web pkg.go.dev