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Agent-to-Agent Synthetic Social Engineering on the Web

Bryan C. Boots

arXiv:2610.33411v1cs.CRcs.MA

TL;DR

Web agents can produce correct reports yet request actions their users have not authorized, while identity, evidence, and permission judgments arise in the same cooperative exchange. The paper operationalizes synthetic social engineering in a controlled testbed and finds that invoking a limited prior agreement increased unauthorized requests from 43.3% to 96.7%.

Abstract

from arXiv · show

An AI agent can prepare an accurate report and still request an action its user has not authorized. Cooperation across Web services therefore requires separate judgments about identity, evidentiary support, and permission. We define synthetic social engineering (SSE) as deliberately deceptive or misleading influence intended to exploit AI recipients' responses to credibility, authority, or obligation cues and redirect behavior away from authorized objectives. We focus on separately tasked sender agents that produce or adapt misleading communication. Drawing on cybersecurity, social engineering, and persuasion research, we develop an operational framework connecting actors, deceptive representations, candidate influence routes, evidence or permission boundaries, responses, and consequences. The framework distinguishes attempts from successful redirection, without assuming human psychological processes. We implement it in the Agent Service Exchange and Evidence Commons (ASE-EC), a reproducible testbed with independently specified records and authorization scopes. Across 1,260 research episodes using Qwen3-4B in two fictional briefing tasks, matched comparisons test authority and commitment appeals, while defense comparisons assess protection alongside authorized task completion. Invoking a limited prior agreement increased unauthorized requests from 43.3% to 96.7%, although recipients retained supported decisions and permissions remained unchanged. These controlled findings identify action selection as a distinct security concern, even when evidence handling succeeds, and they provide a reusable basis for evaluating safeguards that preserve useful cooperation across Web services.

A Web cooperation problem

Web cooperation combines identity, evidentiary support, and permission judgments in the same exchange, even though valid identity or a limited agreement does not establish support or authorize a new action. The paper defines agent-to-agent synthetic social engineering and presents a framework and testbed for examining misleading influence while keeping evidence and permission boundaries explicit.

A Web cooperation problem

  • Agents can discover services and delegate work across independently operated systems, where advice, reports, or limited agreements may be presented as authority, verification, or obligation.Recipients must preserve evidence and permission boundaries while drawing on peers’ assistance.Source: A Web cooperation problem · p. 1
  • Matched encounters vary authority or commitment presentation while holding claims, requested actions, evidence, and actual permissions fixed, separating influence from changes in information or authorization.The commitment comparison preserves the same prior agreement and escalation; adaptive sender encounters are examined separately.Source: A Web cooperation problem · p. 2
  • Synthetic social engineering (SSE) is deceptive or misleading communication intended to redirect an AI agent from authorized objectives; agent-to-agent SSE involves a separately tasked sender producing or adapting misleading material.The framework treats SSE as an attempt, separating its success and any cue’s causal contribution; authority and commitment are candidate influence routes, not assumed human psychological processes.Source: A Web cooperation problem · p. 2
  • The ASE-EC testbed uses inspectable evidence and independently maintained authorization scopes to distinguish unsupported verification, unauthorized requests, and requests from executed actions.An external permission check can block execution without hiding an attempted misuse of authority.Source: A Web cooperation problem · p. 2
  • The paper contributes a bounded SSE framework, controlled tests of authority and commitment claims, and defense evaluations that measure protection alongside clean cooperation and legitimate task performance.The framework links actors and objectives, misleading representations, candidate influence routes, boundary crossings, responses, consequences, and defenses.Source: A Web cooperation problem · p. 2

Defining synthetic social engineering General SSE definition

Synthetic social engineering is deliberate, materially misleading influence that exploits an AI recipient’s responses to social cues to redirect behavior beyond authorized objectives. Its classification depends on the attempted influence, not whether the recipient complies or the action succeeds.

Defining synthetic social engineering General SSE definition

  • SSE is deliberate, materially misleading communication or interaction that uses social cues to induce behavior inconsistent with an AI agent’s authorized objectives.The objectives include the legitimate task, evidence requirements, and action permissions.Source: Defining synthetic social engineering… · p. 2
  • An attempt requires adversarial purpose, material misrepresentation, and an intended influence route; identity or authority language alone is insufficient.A genuine service identity does not establish publication permission, and an unauthorized request alone does not show that a cue caused it.Source: Defining synthetic social engineering… · pp. 2–3
  • Attempt classification, recipient judgment, action request, and completed operation are separate: refusal or a permission check does not erase an attempt.Causal claims about cue effects require comparisons that vary the cue while holding relevant task conditions constant.Source: Defining synthetic social engineering… · pp. 2–3

Agent-to-agent SSE subtype

  • In agent-to-agent SSE, a sender produces or adapts deceptive artifacts for a separately tasked recipient, seeking deviation through misrepresentation of identity, evidence, authority, agreement, or obligation.The sender’s adversarial assignment and bounded communication choices operationalize deliberate pursuit; assignment alone is insufficient, and a static delivery script does not establish agent production or adaptation.Source: Agent-to-agent SSE subtype · p. 3

Construct boundaries and value

  • Ordinary error, honest disagreement, and persuasion within an authorized workflow are not SSE; without evidence of deliberate misleading use for adversarial deviation, classification remains indeterminate.SSE can overlap with prompt injection when deceptive social cues and attacker-controlled instructions both influence the recipient.Source: Construct boundaries and value · p. 3
  • Episode records capture actors, tasks, intended deviation, misleading representation, candidate cue, response, and independent evidence and permission grounds, keeping failed attempts classifiable.This supports testing explanations without assuming success, including when cue effects are positive, null, or heterogeneous.Source: Construct boundaries and value · p. 3

Operational SSE framework and hypotheses Adapting prior scholarship

The framework separates who communicates, what evidence supports a claim, and whether a requested action is authorized, while treating influence attempts and outcomes as distinct. Its hypotheses test authority, commitment, identity checking, and safeguards through observable agent behavior without assuming human psychological processes.

Operational SSE framework and hypotheses Adapting prior scholarship

  • The framework adapts attack stages and deception distinctions while combining adversarial objectives, persuasion routes, and independent request checking [Heartfield and Loukas 2016; Strom et al. 2020; Cialdini 2021; Cialdini and Goldstein 2004; FBI 2024].It treats the text, metadata, and service behavior received by the agent as the relevant representations, without assuming human-directed disguises have the same effect on AI recipients.Source: Operational SSE framework and… · p. 3

Specifying an agent-targeted episode

  • Each episode records encounter, actors and authorized objectives, deceptive representation, candidate influence route, evidence or permission boundary, interaction and persistence, consequence, and defense.Attempt classification is based on the adversarial objective, misleading representation, and intended influence route, independently of outcome. The record keeps communicator identity, evidentiary support, and action permission separate; a correct event capacity may lack required verification support, and a supported brief may still lack publication approval.Source: Specifying an agent-targeted episode · pp. 3–4
  • Least privilege and complete mediation motivate checking every action's scope; requests and executions are scored separately, so a gateway can block publication while exposing an attempted boundary crossing.The example distinguishes an agreement to draft from permission to publish: the peer's commitment appeal does not change the user's release grant.Source: Specifying an agent-targeted episode · p. 4

Research questions and hypotheses

  • Authority substitution tests whether an added authority cue increases unsupported verification when the evidence and request remain unchanged.The matched comparison adds a claimed verification-coordinator role to the same request, with no supporting record and the primary record unavailable.Source: Research questions and hypotheses · p. 4
  • Commitment escalation tests whether invoking an earlier limited agreement increases unauthorized requests, while identity checking alone does not establish a residual cue effect.Both versions include the same agreement and release request; only one invokes the agreement as a reason to comply, and the user's release permission is unchanged. Establishing a residual cue effect under identity/provenance checking requires a matched cue comparison.Source: Research questions and hypotheses · p. 4
  • Targeted defense tests whether evidence and scope checks reduce violations while limiting any decline in clean task success to five percentage points.The joint criterion rejects safeguards that prevent violations by making legitimate work impossible.Source: Research questions and hypotheses · p. 4
  • The hypotheses concern functional responses, not equivalent human psychology; persistence alone does not establish confirmation bias, which would require a separate test of selective evidence retrieval or weighting.The framework connects observable behavior to competing explanations without assuming shared human psychology.Source: Research questions and hypotheses · pp. 4–5

Testbed and experimental methods Shared environment and grounded tasks · Agents, threat model, and control

ASE-EC tests agent cooperation against independently specified evidence and permissions in structured workflows. Its controlled tasks and communication conditions separate evidence judgments from authorization boundaries.

Testbed and experimental methods Shared environment and grounded tasks

  • ASE-EC pairs registered services with an attributed, versioned Evidence Commons, isolating evidence and permission judgments from browser interaction.Its grounded-task evaluation draws on WebArena and WorkArena.Source: Testbed and experimental methods… · p. 5
  • The two briefing tasks test claims about event dates, locations, and capacity or resource types, locations, and quantities.Verification requires designated primary support or warranted report citations; missing evidence requires a null value and uncertainty, while answer keys and adversarial labels are withheld and current records and authenticated grants remain visible.Source: Testbed and experimental methods… · p. 5
  • The task design adapts warranted reliance from human-AI trust research to observable agent decisions.Experiments use protocol 0.3.5 and engine 0.3.5.post1.Source: Testbed and experimental methods… · p. 5

Agents, threat model, and control

  • Each encounter separates coordinator, researcher, verifier, and publisher dialogue contexts, with structured claims, readiness decisions, report assessments, and action requests.Service requests are selected within controller-specified provider choices; roles organize communication without establishing human mental states.Source: Agents, threat model, and control · p. 5
  • All roles use Qwen/Qwen3-4B with greedy decoding at temperature 0, while keeping separate dialogue histories.The setup uses FP16 weights and Transformers 4.57.6; input limits are 12,288 tokens, and histories exceeding the limit are rejected rather than truncated or summarized.Source: Agents, threat model, and control · p. 5
  • Figure 2 illustrates matched event-brief inputs that vary the appeal while keeping the accepted agreement, grant, peer assertion, task context, and model conditions shared.The pair was selected by ordered file availability before recipient outcomes were examined; aggregate paired results, not this example alone, establish the measured effect.Source: Figure 2 · p. 6
  • The sender varies authority and commitment cues while preserving substantive facts and requested actions, and cannot alter instructions, identity, records, or grants.Up to three stimulus-validity attempts enforce wording constraints before recipient evaluation; protecting privileged inputs keeps the task and authorization boundary stable.Source: Agents, threat model, and control · p. 6

SSE framework-driven comparisons

The section tests behavioral claims through matched cue comparisons, adaptive sender-policy comparisons, and defense interventions, distinguishing recipient judgment from enforced permission.

Authority

  • Authority tests cross presentation with evidence availability or actual approval, holding facts, permissions, and service outputs constant within matched pairs.Supported and approved conditions serve as positive controls; the design does not add paraphrase trials or counterbalance incidental names and presentation order.Source: SSE framework-driven comparisons · p. 6

Commitment

  • Commitment tests whether invoking an actual earlier agreement changes responses when the agreement, workflow, and escalation remain the same.The primary comparison replaces a neutral follow-up clause with an appeal to the earlier agreement; preliminary acceptance is recorded, while workflow participation is assessed separately.Source: SSE framework-driven comparisons · p. 6

Adaptive interaction and identity

  • Adaptive interaction compares a frozen sender packet with a responsive sender that uses recipients’ observable replies across two follow-up opportunities.This compares sender policies, not an isolated cue effect; in the example, the actual grant remains unchanged, and residual violations under authenticated-origin and provenance conditions do not by themselves identify a cue effect.Source: SSE framework-driven comparisons · pp. 6–7

Defense

  • Defense comparisons test baseline, provenance, and combined evidence-plus-scope interventions on attack and clean inputs, with a hard gateway enforcing permission in every arm.Evidence-plus-scope combines checking instructions and trusted support validation with current grants; clean controls include required approved actions, so refusal alone is not useful protection. This separates recipient judgment from execution protection.Source: SSE framework-driven comparisons · p. 7

Outcomes, replication, and inference · Results

The results distinguish evidence competence from authorization: recipients could make supported decisions while still requesting unapproved actions. The experiments cover Qwen3-4B in fictional briefing workflows, not independent model replications.

Outcomes, replication, and inference

  • Comparison eligibility was frozen before research and required 90% success on relevant components and 99% protocol validity, without certifying uniform safety.Qualification used 140 episodes to assess protocol validity, evidence handling, readiness, delegation, and authorization separately; baseline security failures remained reported.Source: Outcomes, replication, and inference · p. 7
  • Samples reflected computational constraints, not a claimed power guarantee; earlier pilots were not pooled, and no held-out model evaluation was reported.Scenarios alternated across blocks: 30 per task for authority and commitment, 40 for defense, and 15 for adaptation.Source: Outcomes, replication, and inference · p. 7
  • Primary outcomes were unsupported verification and unauthorized requests, while safe task success additionally required supported decisions, completed services, and authorized actions.Role outcomes, approval assertions, executions, token usage, and cached versus new calls were reported separately.Source: Outcomes, replication, and inference · p. 7
  • Paired effects used 4,000 whole-block bootstrap draws and 4,000 sign flips, with Holm correction across five primary comparisons.The analysis also reported task-specific estimates to address dependence concerns and assessed clean utility against a prespecified five-percentage-point margin using a conservative one-sided 95% bound.Source: Outcomes, replication, and inference · p. 7
  • Scoring required no private reasoning traces, but semantic interpretations lacked blinded intercoder validation.One format-only retry was allowed, incomplete episodes were not scored as zero, resumable sessions journaled raw responses, and all records and actions were fictional and simulated.Source: Outcomes, replication, and inference · p. 7

Results

  • Recipients could preserve uncertainty and make fully supported claims while still requesting actions the user had not approved.The results separate getting the facts right from staying within the authority granted for the task.Source: Results · p. 7
  • All 1,260 research episodes completed, but scenario differences compare workflows within one Qwen3-4B configuration rather than independent model replications.The study reports whole seed/task-block bootstrap intervals and Holm-adjusted primary-family p values; calls and service roles are not independent replications.Source: Results · p. 8
  • 60 of 140 qualification episodes contained unauthorized requests, and ten returned incorrect readiness decisions despite valid claim handling.All 140 episodes satisfied evidence-handling criteria; qualification established prerequisites for specific comparisons, not uniformly safe cooperation.Source: Results · p. 8

Authority and evidence substitution

Claimed authority made no observed difference in matched assays, but outcomes depended on the boundary: unsupported verification remained at the observed floor, while unauthorized requests reached the ceiling without approval.

Authority and evidence substitution

  • Across 60 matched blocks, unsupported verification was zero in both neutral and claimed-authority conditions (0 percentage-point difference; bootstrap interval [0, 0]).The degenerate interval reflects the observed floor and does not establish population immunity or practical equivalence.Source: Authority and evidence substitution · p. 8
  • Correct supported resource-briefing decisions occurred in 80.0% of neutral and 83.3% of claimed-authority cases, although some recipients preserved uncertainty while incorrectly declaring readiness.Because the controller supplied the records, these outcomes do not establish whether recipients actively inspected particular sources.Source: Authority and evidence substitution · p. 8
  • Without approval, unauthorized requests occurred in 60/60 cases under both authority conditions, despite correct supported decisions; with approval, authorized completion was 60/60 in both.The unapproved reference condition was already at the ceiling, so the authority clause produced no observed increment and provides no evidence that it caused the authorization failure.Source: Authority and evidence substitution · p. 8

Consistency and scope expansion

The commitment appeal increased unauthorized requests despite unchanged permissions, while recipients still completed the required workflow and produced correct supported decisions. Secondary controls show that request counts alone do not establish useful security or isolate the appeal’s effect.

Consistency and scope expansion

  • Both conditions completed the required workflow and produced correct supported decisions, while the appeal changed behavior despite identical permissions and proposed action.Every recipient accepted the limited preliminary agreement; the comparison isolates the appeal’s incremental effect within these conditions, but does not establish a human consistency mechanism or exclude other wording explanations.Source: Consistency and scope expansion · p. 8
  • Only 4/60 acknowledgment-control episodes contained an unauthorized request, but 38/60 produced unsupported verification and safe task success was zero.This condition neither demonstrated useful resistance nor isolated the commitment appeal, because workflow participation differed.Source: Consistency and scope expansion · pp. 8–9
  • Unauthorized requests rose from 26/60 (43.3%) without the appeal to 58/60 (96.7%) with it, a paired increase of 53.3 percentage points [41.7, 65.0].Adjusted p = .00125; 32 matched pairs shifted toward an unauthorized request and none shifted in the opposite direction.Source: Consistency and scope expansion · p. 8, Figure 3 · p. 9
  • The no-history control produced unauthorized requests in all 60 episodes while completing the required workflow, but its changed interaction history does not isolate the appeal.Source: Consistency and scope expansion · p. 9

Authentic identity and adaptive interaction

Authenticated peer identities and visible report lineage did not ensure authorized behavior. Fixed and responsive senders both produced violations in every matched episode, but the suite cannot establish equal attack capabilities or estimate cue effects under provenance checks.

Authentic identity and adaptive interaction

  • 61/80 provenance attack cases (76.25%) still involved violations despite controller-authenticated peer identities and visible report ancestry.The study states that authentic identity and visible lineage did not ensure authorized behavior.Source: Authentic identity and adaptive… · p. 9
  • The suite did not cross cue presence with provenance presentation or include a spoofed-identity arm, leaving conditional cue effects unestimated.Identity authenticity, provenance availability, and permission behavior remain distinct properties.Source: Authentic identity and adaptive… · p. 9
  • In 30 matched adaptive-policy blocks, both fixed and responsive senders produced violations in every episode.Unsupported verification occurred in 1/30 fixed-policy episodes and 6/30 responsive-policy episodes; one responsive episode also contained an invalid approval assertion, but these outcomes were descriptive secondary outcomes.Source: Authentic identity and adaptive… · p. 9

Defense, utility, and framework assessment

Evidence-plus-scope checking reduced unauthorized requests, while provenance presentation alone increased them. Protection preserved clean-task success, and execution blocking remained distinct from recipient behavior.

Defense, utility, and framework assessment

  • 76.25% of requests violated authorization with provenance, versus 47.50% under baseline; evidence-plus-scope checking reduced violations to 15.00%.The provenance increase was 28.75 percentage points [16.25, 40.00], and the checking reduction from provenance was -61.25 points [-71.25, -50.00] (both adjusted p = .00125). Residual failure was 27.5% for event briefings and 2.5% for resource briefings.Source: Defense, utility, and framework… · p. 9, Figure 5 · p. 10
  • Provenance supplied lineage rather than permission, and the measured protection concerned authorization, not a separately identified evidentiary benefit.The comparison tested one provenance presentation, and recipient rationales did not establish why it increased violations. Evidence-plus-scope checking combined trusted support checks, scope information, and instructions, so its effect cannot be attributed to cautionary prompting alone.Source: Defense, utility, and framework… · pp. 9–10
  • 80/80 clean cases succeeded under each defense, including 40 requiring approved action, and the utility lower bound of -4.58 points exceeded the -5-point margin.H4 met its violation-reduction and numerical utility criteria in this panel; the scientific meaning of the margin remains open. Findings support H2 and bounded H4, while H1 showed no observed cue effect.Source: Defense, utility, and framework… · pp. 9–10, Figure 5 · p. 10
  • The controller blocked every unauthorized request, preventing unauthorized simulated execution despite unsafe recipient behavior.The framework distinguishes a supported conclusion, an authorized request, and an action permitted to execute.Source: Defense, utility, and framework… · p. 10

Discussion, limitations, and implications What the experiments establish about SSE

The experiments show that supported conclusions and unchanged permissions can coexist with unauthorized requests, while combined evidence-and-scope checking reduced such requests in controlled workflows. The discussion distinguishes SSE attempts from successful redirection and emphasizes limits on what the tested models, workflows, and measures establish.

Discussion, limitations, and implications What the experiments establish about SSE

  • 43.3% to 96.7%: invoking a limited prior agreement increased unauthorized requests while supported conclusions and permissions remained unchanged.This supports an encounter-level influence effect, not a general willingness to accept every misleading claim.Source: Discussion, limitations, and… · pp. 10–11
  • Every unapproved permission-control case produced an unauthorized request with or without apparent authority, while visible identity and provenance did not guarantee appropriate behavior.The reference condition was already at ceiling, so the authority contrast showed no incremental effect; provenance presentation was not crossed with cue presence, and ceiling composite violations could not rank adaptive policies.Source: Discussion, limitations, and… · p. 11
  • SSE attempts are identified by an adversarial objective, materially misleading representation, and intended influence route, separately from success or cue contribution.The commitment appeal resembles presenting limited cooperation as an obligation, but without a human comparison group the study cannot establish shared psychology or compare effect sizes.Source: Discussion, limitations, and… · p. 11

Limitations and alternative explanations

  • Findings are limited to one Qwen3-4B checkpoint, two fictional scenarios, shared model weights, and controller-bounded workflows rather than autonomous discovery or live service negotiation.The commitment comparison best supports causal interpretation, but its appeal may also change relevance or instructional force; adaptive exchanges diverge, and sycophancy does not uniquely explain peer compliance.Source: Limitations and alternative explanations · p. 11
  • Output and request measures do not directly reveal belief, and fewer unauthorized requests can reflect failed delegation rather than protection.The hard gateway prevents completed unauthorized actions by design, so blocked requests show attempted boundary crossing; scoring rules require validation against representative native outputs.Source: Limitations and alternative explanations · pp. 11–12

Implications for Web design

  • Web services should keep identity, evidentiary support, and permission distinct, validating each requested operation against the actual grant before execution.A completed draft is not permission to release it; earlier agreements or report-level approval assertions should not enlarge the grant, and rejected requests should remain visible through logging.Source: Implications for Web design · p. 12

Conclusion

  • The ASE-EC framework makes influence attempts and boundary behavior experimentally assessable, while downstream reliance and recovery across services remain future questions.The study defines SSE as deliberately misleading influence directed at AI recipients to redirect behavior from authorized objectives.Source: Conclusion · p. 12

Implications for Web design

  • 76.25% under provenance presentation fell to 15.0% with combined evidence-and-scope checking, while observed clean-task success was preserved.The intervention included trusted checking assistance, so its components were not separately estimated; the execution gateway blocked every unauthorized request, and findings are bounded to the tested model, tasks, and policies.Source: Conclusion · p. 12, Implications for Web design · p. 12

Appendices

The appendices show an example peer-service request and descriptive joint-outcome summaries for the Event and Resource briefs. The summaries distinguish final safe-task endpoints from unauthorized requests across assessed turns.

Appendices

  • Supplementary Figure 1 shows an actual peer-service request episode from the experiments.Source: Figure 1 · p. 15
  • Supplementary Figures 2–3 give descriptive joint counts by condition for Event and Resource briefs, separating final endpoints from any unauthorized request across assessed turns.The final endpoint requires correct readiness, complete supported claims, and no invalid approval assertion; each cell uses the full observed condition denominator. Workflow completion and joint safe-task success are distinct, and acknowledgment and no-history arms are secondary controls.Source: Figure 2 · p. 16, Figure 3 · p. 17
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