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Tamper Resistance can be bypassed by relocating the directory containing Santa's databases

High
mlw published GHSA-3q7f-8fhv-6m6g Aug 4, 2026

Software

santa

Affected versions

<= 2026.6

Patched versions

2026.7

Description

Summary

Santa's Tamper Resistance did not account for filesystem operations performed on the directory containing its protected state. A process already running as root could move that directory, after which Santa's databases, including the rule database, were reachable for direct read and write at a location Tamper Resistance did not recognize as protected.

Endpoint Security names the directory in such an operation, not the files inside it, and Santa's authorization was keyed to the current path string rather than to the identity of the underlying object. Protection that follows a name does not survive the name changing.

Root is a prerequisite. Tamper Resistance is a defense-in-depth control intended to hold up against a hostile root, so failing to hold that line is a real defect even though root is required.

Impact

An attacker with local root could:

  • Read Santa's protected databases, disclosing the deployed rule set and other local policy state that Tamper Resistance is meant to keep private to santad.
  • Modify execution policy. Rules could be altered, added, or removed in the relocated database, and Santa would subsequently enforce the modified rule set. This can be used to allow binaries that policy should block, or to block binaries that policy should allow.
  • Corrupt or destroy local policy state.

Detection and recovery

For deployments backed by a sync service, this tampering is detectable and recoverable rather than silent. Santa reports a hash of its rule database to the sync server on each sync. A server that compares this against its own view of the client's expected policy will observe the drift and can require a clean sync, which replaces local rules with authoritative server state.

This limits how long tampered policy survives, but note what it is and is not:

  • It is detection and recovery, not prevention. Modified policy is enforced from the moment it is written until the next sync reconciles it.
  • It depends on the sync server actually comparing the reported hash and acting on a mismatch. Workshop does this automatically, with no configuration required. Other sync servers vary.
  • It does not apply to standalone deployments that are not backed by a sync service, where there is no authoritative copy to reconcile against.

What changes in 2026.7

The directory holding Santa's state, and the directories above it, are now protected objects in their own right. Operations that would relocate or duplicate them are denied where they were previously permitted.

This can affect tooling that operates on those directories wholesale. A backup, imaging, or cloning process that recursively copies /private/var or a directory beneath it may now be denied at the protected directories, in the same way it was already denied on the database files themselves.

Affected versions

Field Value
Affected Santa <= 2026.6
Fixed in Santa 2026.7
Severity High, CVSS v4.0 base score 8.4
CVSS CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CWE CWE-284: Improper Access Control, CWE-706: Use of Incorrectly-Resolved Name or Reference

Mitigation

Upgrade to Santa 2026.7 or later. There is no configuration-level workaround in affected versions.

The following are compensating controls that reduce exposure until you can upgrade. None of them close the underlying issue.

  • Limit who can become root. Exploitation requires pre-existing root, so restricting administrative access reduces the population that can attempt it. Workshop customers can use Endpoint Privilege Management to constrain user elevation to root. This narrows the set of users who can reach the required privilege. It does not help against an attacker who obtains root by another route, such as a separate privilege-escalation flaw or an already-root process.
  • Verify sync-side drift detection. Operators running their own sync server should confirm they compare the rule hash reported by clients against expected policy and require a clean sync on mismatch. Workshop does this automatically.
  • Watch for unexpected changes to Santa's state directory.

Credit

Reported by OpenAI Codex Security, Jamie Brim (@jamieb-oai).

Independently reported by @arthurscchan, @DavidKorczynski, and @AdamKorcz. Per that report, the issue was discovered by Claude, Anthropic's AI assistant, with triage and report authoring by Ada Logics in collaboration with Anthropic Research.

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Local
Attack Complexity Low
Attack Requirements None
Privileges Required High
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVE ID

No known CVE

Weaknesses

Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Learn more on MITRE.

Use of Incorrectly-Resolved Name or Reference

The product uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere. Learn more on MITRE.

Credits