Staff Security Engineer

Cohesity is the leader in AI-powered data security. Over 13,600 enterprise customers, including over 85 of the Fortune 100 and nearly 70% of the Global 500, rely on Cohesity to strengthen their resilience while providing Gen AI insights into their vast amounts of data. Formed from the combination of Cohesity with Veritas’ enterprise data protection business, the company’s solutions secure and protect data on-premises, in the cloud, and at the edge. Backed by NVIDIA, IBM, HPE, Cisco, AWS, Google Cloud, and others, Cohesity is headquartered in Santa Clara, CA, with offices around the globe.  
We’ve been named a Leader by multiple analyst firms and have been globally recognized for Innovation, Product Strength, and Simplicity in Design , and our culture. 
Want to join the leader in AI-powered data security? 

We are looking for a highly experienced Staff Engineer with deep expertise in Windows internals, Active Directory internals, and AD security. This is a single, combined role: you will build the Windows agent, model Active Directory at the protocol and database level, and reason about how attackers compromise a directory and how a defender recovers from it. The work spans granular change tracking, object recovery, forest-level backup, identity threat detection, and full forest recovery onto clean operating systems.

• Design and deliver AD protection features: granular change tracking, object- and attribute-level recovery, forest-aware backup, and full forest recovery.
• Build and own the Windows agenta signed, serviceable, silently upgradeable component running on domain controllers.
• Design identity threat detection: change-delta engines, rules for privileged-object and ACL abuse, and the findings pipeline into audit log and SIEM.
• Own the safety of write and restore paths — idempotent steps, USN-rollback safety, pre-flight validation before any destructive action.
• Engage across the security lifecycle: threat modeling, architecture review, attack-surface reduction, vulnerability remediation.
• Work hands-on in code and test automation, including automated recovery drills and fidelity validation.
• Lead projects, mentor engineers, and build Windows and AD depth across the team.

• B.S./M.S./Ph.D. in Computer Science, Electrical Engineering, or a related field.

• 10+ years in software design and development, with significant time on Windows-platform software.
• 5+ years with Active Directory internals — building software that reads, writes, replicates, backs up, or recovers directory data, not only administering it.
• 3+ years security-focused: identity security, detection engineering, security architecture, or product security.
• Shipping agent or systems software onto customer-managed production infrastructure.

• Windows internals: registry and hive structure, the SYSTEM hive and BootKey material, WMI, services, RPC.
• Agent development in C++, C#, or Go; VSS writers and shadow copy APIs — writer sets, freeze/thaw, DiskShadow, orphaned shadows.
• Windows security model: SIDs, tokens, privileges, ACLs and SDDL, impersonation, service accounts.
• Serviceability and transport: code signing, MSI packaging, silent upgrade, mTLS and certificate handling, gRPC agent-to-cluster channels with resumable operations.
• Debugging: WinDbg, ETW, performance counters, dump analysis; PowerShell modules, remoting, and hosting PowerShell from native code.

• Schema, object classes, naming contexts, linked-value replication; safe writes — modify, ModifyDN, object create.
• LDAP at depth: filters, server controls, paged and persistent search, change notification; DirSync and USN cookies for incremental capture.
• Tombstones, deleted-object lifetime, Recycle Bin; SID, SID history and GUID continuity semantics.
• Group Policy internals (GPC/GPT, SYSVOL, DFSR/FRS, authoritative restore); AD-integrated DNS zones, forwarders, delegation.
• Database and topology mechanics: ESE/JET, ntds.dit and logs, esentutl, FSMO, trusts, repadmin/dcdiag, USN rollback, DC promotion, IFM, DSRM, RODC.

• Kerberos and NTLM internals: ticket flow, delegation, krbtgt and its role in forest compromise and recovery.
• AD attack techniques and their detectable artifacts — DCSync, DCShadow, AdminSDHolder tampering, ACL abuse, privileged group manipulation, ticket forgery.
• Detection engineering: deterministic rules with low false-positive rates, baseline-diff and attack-path reasoning; AD auditing and change attribution.
• Cyber recovery of identity: clean-source and clean-OS principles, malware re-introduction risk in image-based restore, isolation during recovery.
• SIEM integration (syslog, CEF, webhooks); threat modeling a component that runs privileged on a domain controller.

• Distributed systems: durable state machines, idempotency, crash recovery and resume, long-running orchestration. Protocols: LDAP, Kerberos, DNS, SMB, TLS, gRPC, REST.
• Test automation for infrastructure software: multi-domain forest labs, destructive recovery drills, upgrade and interop matrices.

• Excellent analytical skills under incomplete information — customer forests are never the lab forest.
• Ability to lead initiatives, mentor, and explain directory-level failure modes to non-specialist audiences.
• Sound judgement about risk. Recovery software gets one chance to be right, and knowing when not to proceed matters as much as knowing how.

• A commercial AD backup, recovery, or ITDR product, or having executed a real forest recovery.
• AD tooling — DSInternals, BloodHound, PingCastle; hybrid identity with Entra ID and Entra Connect.
• Windows kernel or filter driver work; EDR allowlisting; air-gapped or regulated environments.
• Published security work, CVE credits, Red/Blue Team experience; OSCP, GCFA, or equivalent.

• This position is located in our office in Bangalore or Pune, India.

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Equal Employment Opportunity Employer (EEOE)
Cohesity is an Equal Employment Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, creed, religion, sex, sexual orientation, national origin or nationality, ancestry, age, disability, gender identity or expression, marital status, veteran status or any other category protected by law.
If you are an individual with a disability and require a reasonable accommodation to complete any part of the application process, or are limited in the ability or unable to access or use this online application process and need an alternative method for applying, you may contact us at 1-855-9COHESITY or [email protected] for assistance.
In-Office Expectations
Cohesity employees who are within a reasonable commute (e.g. within a forty-five (45) minute average travel time) work out of our core offices 2-3 days a week of their choosing.

We strongly prefer candidates who are currently located in or near the designated job location. Candidates outside the area should apply only if they are committed to relocating prior to their start date and have the legal right to work in the job location.