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JetBrains TeamCity authentication bypass, cited in 2026-05-16 § 3 SentinelOne CI/CD subversion case study

cve · CVE-2023-42793 single-source

Coverage
1
first 2026-05-16 → last 2026-10-21
Latest activity
2026-05-16
SentinelOne: attackers turn build servers, CI/CD runners and developer workstations into the intrusion path
Peak priority
notable
1 notable
Targets
technology
sectors: technology
Sources cited
3
2 hosts

Defender insights

What each entry about CVE-2023-42793 tells a defender to do, newest first.

2026-05-16NOTABLEexploitedSentinelOne: attackers turn build servers, CI/CD runners and developer workstations into the intrusion path

Exposure · triage · detection

Story timeline

  1. 2026-05-16SentinelOne "Living Off the Pipeline": attackers subverted TeamCity, GitLab automation, self-hosted runners and developer workstations in 2025
    researchSentinelOne: attackers turn build servers, CI/CD runners and developer workstations into the intrusion path
ATT&CK techniques (8 across 7 tactics)

8 techniques observed across 1 entry about this entity, derived from entry metadata and body evidence, never asserted without a published entry behind it · pinned to MITRE ATT&CK v20.1 · compare on the matrix · Navigator layer (JSON)

  • Initial AccessValid Accounts · Exploit Public-Facing Application · Supply Chain Compromise: Compromise Software Dependencies and Development Tools · Supply Chain Compromise: Compromise Software Supply Chain · Phishing
  • ExecutionSoftware Deployment Tools · User Execution: Malicious Copy and Paste
  • PersistenceValid Accounts
  • Privilege EscalationValid Accounts
  • StealthValid Accounts
  • Credential AccessUnsecured Credentials
  • Lateral MovementSoftware Deployment Tools

Initial Access TA0001

T1078Valid Accounts×1

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

T1190Exploit Public-Facing Application×1

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

T1195.001Supply Chain Compromise: Compromise Software Dependencies and Development Tools×1

Adversaries may manipulate software dependencies and development tools prior to receipt by a final consumer for the purpose of data or system compromise. Applications often depend on external software to function properly. Popular open source projects that are used as dependencies in many applications, such as pip and NPM packages, may be targeted as a means to add malicious code to users of the dependency. This may also include abandoned packages, which in some cases could be re-registered by threat actors after being removed by the original owner. Adversaries may also employ "typosquatting" or name-confusion by choosing names similar to existing popular libraries or packages in order to deceive a user.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

T1195.002Supply Chain Compromise: Compromise Software Supply Chain×1

Adversaries may manipulate application software prior to receipt by a final consumer for the purpose of data or system compromise. Supply chain compromise of software can take place in a number of ways, including manipulation of the application source code, manipulation of the update/distribution mechanism for that software, or replacing compiled releases with a modified version.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

T1566Phishing×1

Adversaries may send phishing messages to gain access to victim systems. All forms of phishing are electronically delivered social engineering. Phishing can be targeted, known as spearphishing. In spearphishing, a specific individual, company, or industry will be targeted by the adversary. More generally, adversaries can conduct non-targeted phishing, such as in mass malware spam campaigns.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

Execution TA0002

T1072Software Deployment Tools×1

Adversaries may gain access to and use centralized software suites installed within an enterprise to execute commands and move laterally through the network. Configuration management and software deployment applications may be used in an enterprise network or cloud environment for routine administration purposes. These systems may also be integrated into CI/CD pipelines. Examples of such solutions include: SCCM, HBSS, Altiris, AWS Systems Manager, Microsoft Intune, Azure Arc, and GCP Deployment Manager.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

T1204.004User Execution: Malicious Copy and Paste×1

An adversary may rely upon a user copying and pasting code in order to gain execution. Users may be subjected to social engineering to get them to copy and paste code directly into a Command and Scripting Interpreter. One such strategy is "ClickFix," in which adversaries present users with seemingly helpful solutions (such as prompts to fix errors or complete CAPTCHAs) that instead instruct the user to copy and paste malicious code.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

Persistence TA0003

T1078Valid Accounts×1

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

Privilege Escalation TA0004

T1078Valid Accounts×1

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

Stealth TA0005

T1078Valid Accounts×1

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network. Adversaries may choose not to use malware or tools in conjunction with the legitimate access those credentials provide to make it harder to detect their presence.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

Credential Access TA0006

T1552Unsecured Credentials×1

Adversaries may search compromised systems to find and obtain insecurely stored credentials. These credentials can be stored and/or misplaced in many locations on a system, including plaintext files (e.g. Shell History), operating system or application-specific repositories (e.g. Credentials in Registry), or other specialized files/artifacts (e.g. Private Keys).

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

Lateral Movement TA0008

T1072Software Deployment Tools×1

Adversaries may gain access to and use centralized software suites installed within an enterprise to execute commands and move laterally through the network. Configuration management and software deployment applications may be used in an enterprise network or cloud environment for routine administration purposes. These systems may also be integrated into CI/CD pipelines. Examples of such solutions include: SCCM, HBSS, Altiris, AWS Systems Manager, Microsoft Intune, Azure Arc, and GCP Deployment Manager.

Evidence: 2026-05-16/sentinelone-living-off-the-pipeline-ci-cd-subversion-taxonom · ATT&CK page ↗

Entries about JetBrains TeamCity authentication bypass, cited in 2026-05-16 § 3 SentinelOne CI/CD subversion case study (1)

2026-05-16 · view entry permalink →

NOTABLECVE-2023-42793exploitedupdatedNATOB2

SentinelOne "Living Off the Pipeline": attackers subverted TeamCity, GitLab automation, self-hosted runners and developer workstations in 2025

SentinelOne's post of 2026-05-15 describes how attackers in 2025 went after the infrastructure that builds and ships software, not only its dependencies (SentinelOne, 2026-05-15). In one case attackers exploited a vulnerable self-hosted TeamCity server (the post links JetBrains' advisory for CVE-2023-42793), created a benign-looking build configuration that a trusted build agent ran with SYSTEM privileges, deployed a backdoor into internal environments and stayed undetected for more than a year (SentinelOne, 2026-05-15). JetBrains fixed CVE-2023-42793, an unauthenticated remote-code-execution flaw, in TeamCity On-Premises 2023.05.4 (JetBrains, 2023-09-21) and warned that backdoors planted before the patch persist after it (JetBrains, 2023-10-18). In an intrusion from SentinelOne's annual threat report, a compromised GitLab service-account token was used to create projects with malicious Ansible playbooks that the organization's pipeline then executed automatically (SentinelOne, 2026-05-15).

The post's other examples target people and runners: Contagious Interview sent developers in cryptocurrency and blockchain fraudulent job offers leading to fake skill-assessment sites, where a fabricated error told them to run commands that silently installed malware with access to their SSH keys, tokens and credentials, and the Sha1-Hulud campaign registered infected systems as self-hosted GitHub runners under attacker-defined names and used workflows that ran code when someone commented in a repository discussion (SentinelOne, 2026-05-15). Malicious versions of popular build packages ran reconnaissance scripts during installation that harvested tokens and inspected environments, and phished maintainer accounts appended malicious code to legitimate package updates (SentinelOne, 2026-05-15).

Triage: compiling, downloading packages, invoking scripts and opening connections are normal build activity, so a malicious job under a valid service account on a trusted runner looks legitimate unless the account acts outside its role; SentinelOne's discriminators are who created the job, what changed, where the runner was registered and which secrets were accessed (SentinelOne, 2026-05-15).

After gaining access, they created a benign-looking build configuration that was executed by a trusted build agent running with SYSTEM privileges.

The attacker used the token to create projects containing malicious Ansible playbooks, which were then automatically executed by the organization’s CI/CD pipeline.

Build runners should be treated as high-value systems, monitored for suspicious child processes, credential access attempts, reverse tunnels, and persistence mechanisms.

If a malicious job executes under a valid service account on a trusted runner, the behavior may appear legitimate unless the account performs actions that clearly deviate from its role.

SentinelOne 2026-05-15

The vulnerability may enable an unauthenticated attacker with HTTP(S) access to a TeamCity server to perform a remote code execution (RCE) attack and gain administrative control of the TeamCity server.

JetBrains 2023-09-21
Correctionrun 2026-10-21T1148Z-auditaffected_productsbodyclassificationconfidencecvesevidenceheadlinesectorssourcessourcing_notesummarytechniquestitle

The monitoring priorities SentinelOne gives are new runner registrations and unusual runner names, new or modified pipelines created by service accounts, jobs interacting with unfamiliar repositories, workflows that establish network tunnels, and suspicious child processes, credential access attempts, reverse tunnels and persistence on build runners (SentinelOne, 2026-05-15); the post names no audit-event type, source-address criterion or specific binaries. It walks through examples rather than a three-case taxonomy, and the rogue self-hosted runners and discussion-comment workflow triggers belong to the Sha1-Hulud campaign (SentinelOne, 2026-05-15). The TeamCity case links CVE-2023-42793, an unauthenticated remote-code-execution flaw fixed in TeamCity On-Premises 2023.05.4 (JetBrains, 2023-09-21); JetBrains warns that backdoors planted before patching are likely to persist after it, so a server patched after early October 2023 needs a compromise assessment (JetBrains, 2023-10-18).

research16 May 05:00Zsingle-sourceOpen finding →

Co-occurring entities

Derived: referenced by the same focused operational entries (weekly summaries and report roundups don't count); ×N counts the shared entries.

Where this entity is cited

  • Research1

Source distribution

  • blog.jetbrains.com2 (67%)
  • sentinelone.com1 (33%)