CVE-2026-77585

Executive Summary

CVE-2026-77585 is an unpatched command-line argument injection vulnerability in the Okta Privileged Access client. The client fails to reject a leading hyphen in the username portion of an SSH target string, allowing the value to be interpreted as a command-line option by the underlying SSH binary. An attacker who can influence the SSH target string (e.g., via a malicious jump host, directory entry, or user-supplied alias) can cause the SSH client to process unintended command-line flags, potentially enabling file disclosure, credential theft, or command execution on the client host. The vulnerability carries a CVSS score of 5.3 (Moderate) under vector CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N, reflecting a high confidentiality impact under low-privilege, user-interaction-dependent conditions. No public exploit code or vendor patch exists at the time of writing.

Technical Analysis

The vulnerability class is argument injection (CWE-78: Improper Neutralization of Special Elements used in an OS Command). The flaw resides in the Okta Privileged Access client's parsing of SSH target strings. When a user (or an automated process) provides an SSH target in the form [username@]hostname, the client does not validate whether the username field begins with a hyphen (-). This is significant because Unix command-line parsers universally treat arguments beginning with a hyphen as options/flags rather than positional parameters.

In a typical SSH invocation (e.g., ssh [options] [user@]hostname [command]), the SSH binary uses getopt(3) or similar parser logic. If the Okta client constructs a command similar to ssh <target>, and <target> is attacker-controlled, then setting the username portion to something like -oProxyCommand=... would cause the SSH process to interpret -oProxyCommand as an option rather than a literal username. The technical mechanism is predictable: the client fails to apply a defensive check (e.g., rejecting any username that starts with -, or forcing the use of -- to signal the end of option parsing). Without this check, the SSH client's native option parser is exposed directly to content intended to be treated as data.

The attack surface is limited to scenarios where an attacker can influence the username field of an SSH target that the Okta Privileged Access client subsequently passes to the underlying SSH process. This may occur when:

• A user clicks a crafted link or copies a malicious target string from an untrusted source.
• The Okta client integrates with directory services (e.g., LDAP/AD) where display names or aliases are attacker-controllable.
• An internal tool or script constructs SSH targets from external input without sanitization.

The CVSS vector confirms the local, low-complexity (though high attack complexity) nature: AV:L (Local), AC:H (High complexity), PR:N (None required), UI:R (User interaction required), S:U (Unchanged scope), C:H (High confidentiality impact), I:L (Low integrity impact). The high confidentiality rating suggests the most likely exploitation path involves reading local files (e.g., via -oProxyCommand or -oIdentityFile options) or exfiltrating SSH keys. The low integrity impact may stem from the ability to modify session configuration without full system compromise.

No patch evidence exists (0/4 patch confidence). The vendor has not released a fix, a version range, or a workaround, and no public advisory has been issued.

Exploitation Scenarios

No public PoC or exploit code is available; the attack chain below is inferred from the vulnerability class (argument injection in an SSH client).

1. Reconnaissance / Target Identification: An attacker identifies an environment using Okta Privileged Access for SSH session management. The attacker determines the client's user interface and how SSH targets are constructed (e.g., via the Okta web portal, CLI flags, or configuration files). The key pre-condition is that the attacker can influence the username component of an SSH target string that a victim will process.

2. Triggering the Flaw: The attacker crafts a payload in the username field that begins with a hyphen. For example, the attacker sends the victim a link or config entry such as -oProxyCommand=...@legitimate-host — where the username field is -oProxyCommand=... and the host is a benign SSH server. When the Okta client builds the SSH command, the leading hyphen in the username causes the underlying SSH process to treat -oProxyCommand as a command-line option rather than a literal username.

3. Payload / Execution Method (vulnerability-class level): Because CWE-78 argument injection enables arbitrary option injection into a command-line binary, the attacker can leverage SSH's native options to achieve impact:

   • File disclosure (C:H): Via -oIdentityFile=/path/to/file followed by a fake key, or via -F to load an alternate config file, the attacker may read file contents through error messages or side-channel behavior.
   • Command execution: Via -oProxyCommand="<shell-command>", the SSH client executes the specified command locally before establishing the SSH connection. This would achieve arbitrary command execution on the victim host.
   • Credential theft: Via -oUserKnownHostsFile or -oGlobalKnownHostsFile options, the attacker can redirect known-hosts files or key material to a location under their control.

   The exact payload structure and whether OpenSSH's option parser permits all these flags without error is not publicly documented for this CVE, and the high attack complexity (AC:H) suggests some payloads may require precise formulation or may be limited by the client's argument pre-processing.

4. Post-Exploitation Impact: Successful exploitation yields high confidentiality impact (reading sensitive files such as SSH keys, credentials, or config files) and low integrity impact (unintended configuration changes to the SSH session). Because the scope is unchanged (S:U), the attacker does not pivot beyond the affected client process. However, harvested SSH keys may be reused against other internal systems.

Impact Assessment

• Business Impact: Moderate. The vulnerability affects end-user workstations and administrators' machines that run the Okta Privileged Access client and process SSH targets. A successful attack could expose SSH private keys, configuration files, or other sensitive data stored on the victim host, compromising downstream systems accessible via those keys. The low integrity impact suggests limited ability to alter data, reducing but not eliminating overall risk.
• Affected Systems: Any deployment of the Okta Privileged Access client where users or automated processes accept SSH target strings from untrusted sources. Because the client is typically positioned as a secure gateway to privileged infrastructure, a compromise of the client host may also weaken audit trails and central session management.
• Blast Radius: Restricted to the local client host due to AV:L and S:U. The high confidentiality subscore (C:H) indicates that if exploited, the confidentiality impact to the victim is severe — primarily through file disclosure. The attack complexity is high (AC:H), which may require the attacker to have prior knowledge of the victim's SSH configuration or to overcome client-side input validation beyond the missing hyphen check.
• CVSS Reference: 5.3 (Moderate) — CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N.

Detection Guidance

Sigma Rule

title: Okta Privileged Access SSH Target with Leading Hyphen in Username
id: 3e6f8e1a-5c4b-4b2e-9a3f-123456789abc
status: experimental
description: Detects attempts to pass an SSH target with a username beginning with a hyphen to the Okta Privileged Access client, indicating possible argument injection.
logsource:
    product: windows
    service: sysmon
detection:
    selection:
        EventID: 1
        Image|endswith:
            - '\okta_privileged_access.exe'
            - '\ssh.exe'
        CommandLine|contains|all:
            - ' -'                # space followed by hyphen (option start)
            - '@'                 # indicates user@host format
    filter_known_safe:
        CommandLine|contains:
            - ' -p '              # port option is legitimate
            - ' -l '              # login name option
    condition: selection and not filter_known_safe
level: high

YARA Rule

rule Okta_Privileged_Access_ArgInjection_CVE_2026_77585 {
    meta:
        author = "Valterit Security Research"
        description = "Detect strings resembling Okta Privileged Access SSH target argument injection"
        cve = "CVE-2026-77585"
        date = "2026-01-01"
    strings:
        $ssh_opt_proxy = /-[a-zA-Z]+\s*=\s*\S+@\S+/ ascii nocase
        $ssh_opt_o      = /-[a-zA-Z]+\s*=/ ascii nocase
        $leading_hyphen = /^-\w+@/ ascii
        $okta_client    = "okta" ascii nocase
    condition:
        (uint16(0) == 0x5A4D or uint32(0) == 0x464C457F) and
        $okta_client and
        ($ssh_opt_proxy or ($ssh_opt_o and $leading_hyphen))
}

Suricata IDS Rule

Suricata is network-based; given the local nature of this vulnerability, detection is limited to scenarios where SSH commands are transmitted via protocols such as Telnet, or where a management service passes commands to agents.

alert tcp any any -> any any (msg:"Okta Privileged Access SSH Target Argument Injection (CVE-2026-77585)"; flow:established,to_server; content:"ssh"; nocase; pcre:"/\s-o\w+\s*=\s*/i"; pcre:"/\s-\w+@/i"; reference:cve,2026-77585; classtype:attempted-user; sid:2026775851; rev:1;)

Note: Due to encryption inherent in SSH traffic, this rule has limited utility; network detection is best paired with endpoint logging.

Elastic Detection

sequence by host.name with maxspan=5m
  [ process where event.action == "exec" and
      process.name == "okta_privileged_access.exe" and
      process.command_line : "*-*@*" ]
  [ process where event.action == "exec" and
      process.name == "ssh.exe" and
      process.command_line : "*-*@*" and
      (process.command_line : "*-o*" or process.command_line : "*-l*") ]

Splunk SPL Query

index=endpoint sourcetype=ProcessRollup2 OR sourcetype=XmlWinEventLog
| where Image LIKE "%\\okta_privileged_access.exe%" OR Image LIKE "%\\ssh.exe%"
| regex CommandLine=" -\w+@"
| search CommandLine="-o\w+=" OR CommandLine="-l\w+="
| stats count min(_time) as earliest max(_time) as latest by host, user, Image, ParentImage, CommandLine
| sort - count

Wazuh OSSEC Rule

<group name="okta_privileged_access,">
  <rule id="182034" level="12">
    <if_sid>550</if_sid> <!-- Linux audit or execve rule -->
    <regex>-\w+@\S+</regex>
    <field name="file">okta_privileged_access</field>
    <description>Okta Privileged Access: SSH target username begins with hyphen (CVE-2026-77585)</description>
    <group>sshd,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence is 0/4 — UNPATCHED. No vendor fix, no version numbers, and no CVE-related advisory are currently available.

1. Immediate Mitigations (compensating controls):

   • User awareness training: Instruct all users of Okta Privileged Access to only open SSH targets from trusted, vetted sources. Do not click links or paste SSH connection strings from untrusted emails, chats, or web pages.
   • Egress filtering: Implement outbound firewall rules to restrict SSH connections to a defined allowlist of production hosts. This limits the reach of the underlying SSH client even if an argument injection payload is processed.
   • EDR monitoring: Deploy or tune endpoint detection rules to flag any invocation of ssh.exe (or equivalent) from the Okta client where the command line contains a username segment beginning with a hyphen. Treat such events as suspicious.
   • Restrict local admin rights: Limit which users can install or run the Okta Privileged Access client on sensitive workstations. The CVSS user-interaction requirement means that a smaller user base reduces exposure.

2. Patch / Upgrade Steps:

   • Visit the official Okta status page and Okta Privileged Access product documentation for the next software release.
   • Subscribe to Okta security bulletins.
   • When a patch is released, apply it to all clients via the Okta-managed update mechanism or enterprise software deployment tooling (e.g., Intune, SCCM, Jamf) as soon as possible.
   • Until a fix is available, verify that the client is updated to the latest build periodically, as other unrelated security fixes may still ship.

3. Long-Term Hardening:

   • Architectural controls: Consider whether the Okta privileged Access client can be deployed in a "thin client" or session manager mode that does not invoke a local SSH binary directly on the endpoint.
   • Request vendor fix: Open a case with Okta support referencing CVE-2026-77585 and request a timeline for a patch that either rejects hyphens in usernames or wraps the target argument with -- before passing it to SSH.
   • Security reviews: Add a regression test to any internal security validation suite that verifies the Okta client's handling of SSH target strings.
   • Network segmentation: Ensure that jump hosts and privileged systems are separated from general user workstations, reducing the value of any SSH keys that may be exfiltrated.

References

1. NVD Entry — https://nvd.nist.gov/vuln/detail/CVE-2026-77585
2. Mitre ATT&CK — T1210 — Exploitation of Remote Services: https://attack.mitre.org/techniques/T1210/
3. CWE-78 — Improper Neutralization of Special Elements used in an OS Command: https://cwe.mitre.org/data/definitions/78.html
4. Okta Security Advisories (official page for future updates): https://trust.okta.com/security-advisories/
5. CISA Known Exploited Vulnerabilities Catalog (CVE not currently listed): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Threat actor campaigns / exploit-in-the-wild evidence: None known at the time of writing. CISA KEV status is NO. No public PoC, exploit code, or Nuclei template exists. This CVE is not currently associated with any tracked APT or cybercrime campaign.