{"licence":{"name":"CC BY-SA 4.0","spdx":"CC-BY-SA-4.0","url":"https://creativecommons.org/licenses/by-sa/4.0/","attribution":"Atlas, a bilingual technical dictionary (https://cmaintz.github.io/tech-atlas/)"},"id":"security/supply-chain-attack","url":{"en":"https://cmaintz.github.io/tech-atlas/en/terms/security/supply-chain-attack/","da":"https://cmaintz.github.io/tech-atlas/da/terms/security/supply-chain-attack/"},"term":{"en":"Supply chain attack","da":"Forsyningskædeangreb"},"aka":{"en":["supply chain compromise"],"da":["supply chain-angreb","leverandørangreb"]},"domain":["security"],"cluster":"fundamentals","layer":"governance","status":"current","summary":{"en":"Breaking into many targets at once by first taking over a supplier, product or update they all trust.","da":"At ramme mange mål på én gang ved først at overtage en leverandør, et produkt eller en opdatering, som de alle stoler på."},"body":{"formal":{"en":"An attack that does not go at the target directly but plants harmful code or access in something the target gets from a third party - software, an update, an open source library, a service provider - so the target installs or lets in the attacker itself.","da":"Et angreb, der ikke går direkte efter målet, men planter skadelig kode eller adgang i noget, målet får fra en tredjepart - software, en opdatering, et open source-bibliotek, en serviceleverandør - så målet selv installerer eller lukker angriberen ind."},"plain":{"en":"Like poisoning the flour at the mill instead of breaking into every bakery - each baker uses it in good faith.","da":"Som at forgifte melet på møllen i stedet for at bryde ind i hvert bageri - hver bager bruger det i god tro."},"inPractice":{"en":"Attackers break into the build system of a widely used network monitoring tool and hide a backdoor in its next update; IT staff at Danish municipalities and firms install the signed update as usual and let the attackers in.","da":"Angribere bryder ind i byggesystemet hos et udbredt værktøj til netværksovervågning og gemmer en bagdør i den næste opdatering; IT-folk i danske kommuner og virksomheder installerer den signerede opdatering som normalt og lukker angriberne ind."},"whyItMatters":{"en":"One successful break-in pays off many times over, and victims who did everything right can still be hit, so the trust we place in suppliers must itself be checked.","da":"Ét vellykket indbrud giver gevinst mange gange, og ofre, der gjorde alt rigtigt, kan stadig blive ramt; derfor skal den tillid, vi har til leverandører, også selv kontrolleres."}},"deepDive":{"en":"A supply chain attack subverts the trust relationship between an organisation and something it consumes from a third party, so the victim installs or authorises the compromise itself. MITRE ATT&CK catalogues the technique as T1195 (Supply Chain Compromise), with sub-techniques covering the software development environment, the software update mechanism and hardware. Attacks are usually classified into software supply chain (build systems, dependencies, updates, code-signing infrastructure) and hardware or third-party service compromise (a managed service provider, an OAuth-connected SaaS app, an outsourced help desk). The strategic appeal is leverage: one compromise upstream propagates to many downstream victims through a channel they already trust and often through signed, seemingly legitimate artefacts.\n\nTwo landmark cases define the modern understanding. In the 2020 SolarWinds Orion incident, attackers compromised the vendor's build pipeline and inserted the SUNBURST backdoor into a signed update distributed to thousands of organisations, demonstrating that a valid code signature attests only to who built an artefact, not that the artefact is benign. In 2024 the xz-utils / liblzma backdoor (CVE-2024-3094) showed the open-source variant: a maintainer identity was cultivated over years to insert an obfuscated backdoor into a widely used compression library feeding OpenSSH on many Linux distributions, caught by chance before broad release. Together they illustrate the two dominant vectors - compromising a commercial build/distribution channel, and compromising the open-source dependency graph, where transitive dependencies mean an application trusts code it never directly chose.\n\nDefences focus on provenance, integrity and verification across the software lifecycle. A Software Bill of Materials (SBOM), in formats such as SPDX or CycloneDX, inventories components so that a newly disclosed vulnerability can be located quickly. Build-integrity frameworks (SLSA) and reproducible builds raise assurance that a released artefact corresponds to reviewed source; signing and transparency systems (Sigstore, in-toto attestations) bind artefacts to their provenance; dependency pinning, lockfiles and vetting reduce exposure to malicious or typosquatted packages. NIST SP 800-161 provides cyber supply-chain risk-management guidance. Regulation now mandates much of this: NIS2 Article 21 explicitly requires supply-chain security among its risk-management measures, and the EU Cyber Resilience Act obliges product manufacturers to manage vulnerabilities across components, with reporting duties applying from 11 September 2026. In OWASP Top 10:2025 this area is elevated to A03 Software Supply Chain Failures.\n\nA central misconception is that a valid digital signature or a reputable vendor guarantees safety; both SolarWinds and xz-utils delivered maliciously modified but properly signed or officially distributed code. Another is scoping supply chain to purchased software only, ignoring open-source dependencies, CI/CD tooling, container base images and connected SaaS, which are equally part of the attack surface. Supply chain attack is a delivery strategy rather than a payload, distinct from the malware or backdoor it plants and from a direct intrusion; its defining feature is that the trust an organisation places in its suppliers must itself be treated as an attack surface to be verified.","da":"Et forsyningskædeangreb undergraver tillidsforholdet mellem en organisation og noget, den forbruger fra en tredjepart, så offeret selv installerer eller godkender kompromitteringen. MITRE ATT&CK katalogiserer teknikken som T1195 (Supply Chain Compromise) med underteknikker, der dækker udviklingsmiljøet, opdateringsmekanismen og hardware. Angreb klassificeres typisk i software supply chain (byggesystemer, afhængigheder, opdateringer, infrastruktur til kodesignering) og kompromittering af hardware eller tredjepartstjenester (en managed service provider, en OAuth-forbundet SaaS-app, en outsourcet helpdesk). Den strategiske tiltrækning er løftestangseffekten: én kompromittering opstrøms breder sig til mange ofre nedstrøms gennem en kanal, de allerede stoler på, og ofte via signerede, tilsyneladende legitime artefakter.\n\nTo skelsættende sager definerer den moderne forståelse. I SolarWinds Orion-hændelsen i 2020 kompromitterede angribere leverandørens build-pipeline og indsatte SUNBURST-bagdøren i en signeret opdatering, der blev distribueret til tusindvis af organisationer, hvilket viste, at en gyldig kodesignatur kun attesterer, hvem der byggede et artefakt - ikke at artefaktet er ufarligt. I 2024 viste xz-utils/liblzma-bagdøren (CVE-2024-3094) open source-varianten: en vedligeholderidentitet blev opdyrket over år for at indsætte en sløret bagdør i et udbredt komprimeringsbibliotek, der fødte OpenSSH på mange Linux-distributioner, opdaget ved et tilfælde før bred udrulning. Tilsammen illustrerer de de to dominerende vektorer - at kompromittere en kommerciel build-/distributionskanal og at kompromittere open source-afhængighedsgrafen, hvor transitive afhængigheder betyder, at en applikation stoler på kode, den aldrig direkte har valgt.\n\nForsvar fokuserer på proveniens, integritet og verifikation gennem hele softwarens livscyklus. En Software Bill of Materials (SBOM) i formater som SPDX eller CycloneDX inventariserer komponenter, så en nyoplyst sårbarhed hurtigt kan lokaliseres. Rammeværker for build-integritet (SLSA) og reproducerbare builds hæver sikkerheden for, at et udgivet artefakt svarer til gennemgået kildekode; signerings- og transparenssystemer (Sigstore, in-toto-attestationer) binder artefakter til deres proveniens; pinning af afhængigheder, lockfiles og vetting reducerer eksponeringen mod ondsindede eller typosquattede pakker. NIST SP 800-161 giver vejledning i cyber supply chain-risikostyring. Regulering påbyder nu meget af dette: NIS2 artikel 21 kræver eksplicit forsyningskædesikkerhed blandt sine risikostyringsforanstaltninger, og EU's Cyber Resilience Act forpligter produktproducenter til at håndtere sårbarheder på tværs af komponenter, med indberetningspligter, der gælder fra 11. september 2026. I OWASP Top 10:2025 er dette område løftet op til A03 Software Supply Chain Failures.\n\nEn central misforståelse er, at en gyldig digital signatur eller en velrenommeret leverandør garanterer sikkerhed; både SolarWinds og xz-utils leverede ondsindet modificeret, men korrekt signeret eller officielt distribueret kode. En anden er at afgrænse forsyningskæden til købt software alene og se bort fra open source-afhængigheder, CI/CD-værktøjer, container-baseimages og forbundne SaaS, som er lige så meget en del af angrebsfladen. Et forsyningskædeangreb er en leveringsstrategi snarere end en payload, forskellig fra den malware eller bagdør, det planter, og fra et direkte indbrud; dets definerende træk er, at den tillid, en organisation har til sine leverandører, selv må behandles som en angrebsflade, der skal verificeres."},"edges":[{"type":"requires","to":"security/malware","confidence":"high","strength":"normal"},{"type":"kind-of","to":"security/threat","confidence":"high","strength":"normal"},{"type":"exploits","to":"platform/software-supply-chain","why":{"en":"Every outside library, build tool and update is a link the attacker can take over to reach everyone further down the chain.","da":"Hvert eksternt bibliotek, byggeværktøj og hver opdatering er et led, angriberen kan overtage for at nå alle længere nede i kæden."},"confidence":"high","strength":"primary"},{"type":"causes","to":"security/data-breach","why":{"en":"The planted backdoor gives the attacker a trusted way in to read or steal the victims' data.","da":"Den plantede bagdør giver angriberen en betroet vej ind til at læse eller stjæle ofrenes data."},"confidence":"high","strength":"normal"}],"depth":3,"sources":[{"title":"MITRE ATT&CK - T1195 Supply Chain Compromise","url":"https://attack.mitre.org/techniques/T1195/","tier":"reference","publisher":"MITRE"},{"title":"CISA & NIST - Defending Against Software Supply Chain Attacks (2021)","tier":"official-doc","publisher":"CISA"}],"draft":true}