Changed since version 26

• Renumbered sources to this input: The Hacker News S1, FortiGuard S2, SecurityWeek S3, CISA KEV S4, CISA alert S5. Unit 42 is retained as S6 for artifacts only it supplies.
• Added the iked tag-based VPN validation bypass to what_happened, verify and contain, as a vendor-stated behavior [S1].
• Added a debrief gap and an open question on the VPN tag format and the unsourced 8550/169.254.0.1 markers [S1].
• Added the SecurityWeek follow-up (2026-10-20) to the timeline. Its content remains unreadable and uncorroborating [S3].
• Filled eradicate, reenter_when, coverage_checks and timeline, which were absent or truncated in the prior draft.

What happened

• CL-STA-0954 (aka UNC5820) gained initial access to a telecom MSP's FortiManager through FortiJump (CVE-2024-47575) [S1].
• The actor exfiltrated running configs, cryptographic material and database files for more than 500 managed FortiGates [S1].
• Using that material, the actor set up unauthorized SSL/VPN sessions to perimeter firewalls [S1].
• The actor exploited CVE-2025-61624 to deploy PEERSTITCH. An auto-script downloaded five components from 23.240.77.233:8085, and the injector ptrace-injected into /bin/miglogd and /bin/iked [S1].
• The hooked iked checks VPN sessions for an actor tag. Tagged sessions take an alternative path that bypasses default FortiOS security validations [S1].
• CISA added CVE-2025-61624 to KEV on 2026-10-16 based on evidence of active exploitation [S4][S5].

Timeline

Detect

FortiGate auto-script objects with path traversal names · FortiOS system event / config change logs (syslog or FortiAnalyzer forward)

index=* devid=* type="event" subtype="system" (cfgpath="system.auto-script" OR msg="*auto-script*") (cfgobj="*../*" OR msg="*../*") | stats count min(_time) as first_seen max(_time) as last_seen values(action) as action values(cfgobj) as cfgobj values(msg) as msg by devname user ui

A hit means: An auto-script object with ../ in its name was created, edited or deleted. Unit 42 names ../../../../setup and ../../tmp/apache2/conf/md-acme.conf [S6]. Treat a hit as likely compromise. The actor deletes auto-scripts after execution, so a delete event alone matters [S1].

Traffic, web or SSL-VPN sessions involving campaign infrastructure · FortiGate traffic, web filter and VPN event logs; proxy/egress logs

index=* (srcip IN ("23.240.77.233","47.18.167.159","45.32.41.202","198.199.122.22") OR dstip IN ("23.240.77.233","47.18.167.159","45.32.41.202","198.199.122.22") OR remip IN ("23.240.77.233","47.18.167.159","45.32.41.202","198.199.122.22") OR url="*/pM.js" OR (dstport=8085 (url="*/a.js" OR url="*/a.wasm" OR url="*/b.js" OR url="*/dd")) OR (dstport=8084 (url="*/acme/*" OR url="*/directory")) OR url="*/acme/new-acct*" OR url="*/acme/finalize/*" OR url="*/acme/order/*" OR url="*/acme/authz/*") | stats count min(_time) as first_seen max(_time) as last_seen values(dstport) as dstport values(url) as url values(action) as action values(user) as user by devname srcip dstip

A hit means: A device contacted campaign infrastructure. A fetch of pM.js, a.js, a.wasm, b.js or dd from 23.240.77.233:8085 matches the component download [S1]. The other IPs and the port 8084 /directory and /acme/ paths come from Unit 42's mod_md SSH reverse-shell findings [S6]. Inbound SSL-VPN logins from these IPs match stolen-credential use [S1][S6]. ACME paths alone can be benign if the peer is not a campaign IP.

Logging daemons killed, crashlogs cleared, or FortiGateCloud admin activity · FortiOS CLI audit and system event logs

index=* devid=* (msg="*killall*miglogd*" OR msg="*killall*syslogd*" OR msg="*crashlog clear*" OR user="FortiGateCloud") | stats count min(_time) as first_seen max(_time) as last_seen values(msg) as msg values(ui) as ui by devname user

A hit means: Someone stopped logging or cleared crash logs, matching the actor's log tampering [S1]. An admin named FortiGateCloud pulling running configs matches the FortiManager impersonation [S1][S6]. Also check each device's syslog stream for gaps. A successful kill produces silence, not events.

Rogue Virtual FortiGate registration on FortiManager · FortiManager event / device management logs

index=* ("FMG-VMTM23017412" OR ("Virtual FortiGate" AND "localhost") OR ".tm") devid=* | stats count min(_time) as first_seen max(_time) as last_seen values(msg) as msg by devname

A hit means: The rogue Virtual FortiGate (localhost, serial FMG-VMTM23017412) appears, or a .tm archive is referenced [S6]. Treat the FortiManager and every device it manages as in scope. Absence does not clear you, because the actor may use other serials. The bare .tm term is noisy, so confirm by context.

Verify

• Pull config revisions on each FortiGate. Look for auto-script objects containing ../ and for admins or VPN groups that were created and then deleted [S1][S6].
• Run diagnose debug crashlog read. Signal 11 crashes in miglogd, iked or syslogd are a reported indicator [S6].
• pM.js deletes itself, so its absence does not clear a device [S1]. Check /data2/template/ for leftover lldprx, ipssem.js, index.js and index.wasm [S6].
• Hash recovered files against Unit 42's published SHA-256 values. Scan them with YARA rule u42_apt_linux_PEERSTITCH_fortigate_implant [S6].
• Inspect Apache mod_md job.json for MDChallengeDns01 mapped to /bin/node. Look for SSH arguments such as kali@23.240.77.233:8084 with -F /tmp/upfile/ssh_config [S6].
• Check /proc/<pid>/maps of /bin/miglogd and /bin/iked for anonymous 16,384-byte rwxp regions [S6]. PEERSTITCH ptrace-injects code into both processes [S1].

Scope

Affected

• FortiOS, FortiPAM, FortiProxy and FortiSwitchManager (CVE-2025-61624) [S4][S5]
• FortiManager (CVE-2024-47575), the initial access in this campaign [S1]
• FortiGates managed by a compromised FortiManager, whose configs and keys were exfiltrated [S1]

Only if

• CVE-2025-61624 requires an authenticated attacker with an admin profile that has read-write permissions. That attacker can then write or delete arbitrary files via specific CLI commands [S4][S5].
• In this campaign, that access followed configs, credentials and keys taken via the compromised FortiManager [S1].

Not affected if

None stated by the sources.

Fixed in: See Fortinet FG-IR-26-122 [S2]. The provided material does not state fixed versions.

Enumerate

• List every FortiOS, FortiPAM, FortiProxy, FortiSwitchManager and FortiManager instance, with its running version.
• For each FortiManager, list registered devices, unknown Virtual FortiGates, .tm archives, and the FortiGates it manages [S6].
• List all admin accounts, VPN users and groups, including deleted ones visible in config revisions [S1].
• List sniffer configs on FortiGates, especially those capturing TCP 3696-3706, UDP 69, 1812/1813 or TCP 389 [S6].
• List secrets stored in FortiGate configs: admin and VPN credentials, pre-shared keys, certificates, and RADIUS/LDAP binds [S1].
• Map management and FGFM (TCP 541) exposure per device, and the hosts each FortiGate accepts management connections from [S1][S6].

Contain

• Before patching or rebooting, export config revisions, event logs and crash logs. With vendor support, capture memory of miglogd and iked, where PEERSTITCH runs [S1]. A reboot destroys in-memory artifacts and cannot be undone.
• Block 23.240.77.233 [S1], and 47.18.167.159, 45.32.41.202 and 198.199.122.22 [S6], at egress and for SSL-VPN.
• Block outbound SSH from firewall management addresses unless required. The actor used mod_md to spawn SSH reverse shells [S1].
• Restrict management and FGFM access to known FortiManager and admin hosts. Remove internet exposure of FortiManager and admin interfaces.
• Disable unknown admins and VPN accounts. Remove unauthorized sniffer configs and rogue FortiManager device registrations [S1][S6].
• Terminate active SSL-VPN sessions on suspect devices. The iked hook can hide tagged sessions from normal validation [S1].
• If a FortiManager may be compromised, rotate every credential and key stored in FortiGate configs [S1]. Rotation does not undo exposure of data already taken.
• Apply FG-IR-26-122 and the FortiManager fix for CVE-2024-47575. Where patching lags, confirm FortiGuard virtual patch FG-VD-59270.0day (FMWP db 25.120) is in place [S2].

Eradicate

• Remove rogue auto-scripts, admin accounts, VPN groups and sniffer configs [S1][S6].
• Remove PEERSTITCH components: lldprx, ipssem.js, index.js, index.wasm and the downloaded a.js, a.wasm, b.js and dd [S1][S6].
• Remove the mod_md job.json changes that spawn SSH [S6].
• Reflash or reimage affected FortiGates from trusted firmware. Clear injected code in miglogd and iked [S1].
• Close the root causes: patch CVE-2024-47575 on FortiManager and CVE-2025-61624 on devices [S1][S2].

Recover

• Before restoring, confirm patched firmware, a config matching a known-good baseline, and rotated secrets [S2].
• Confirm syslog flows continuously from each device and that crash logs are retained [S1].
• Confirm no 16KB rwxp regions remain in miglogd and iked, and that the published YARA rule finds nothing [S6].
• Afterwards, keep the four hunts running. Alert on new auto-scripts, short-lived admins, sniffer config changes, outbound SSH from firewalls, unexpected FGFM peers and logging gaps [S1][S6].

Re-enter the loop when

• New IoCs, hashes or C2 addresses are published for PEERSTITCH or CL-STA-0954.
• Fortinet revises FG-IR-26-122, for example with fixed versions, more affected products or new indicators [S2].
• Evidence shows PEERSTITCH persists across reboot or firmware upgrade.
• A hunt hits on a device not managed by a compromised FortiManager, meaning scope is wider than first thought.
• CVE-2024-26008 or CVE-2024-26009 is confirmed as part of the chain.

Debrief

• Record each device, version, patch date, evidence captured and hunt results.
• Record which secrets were rotated and when, and any logging gaps found.
• Record VPN sessions that could not be validated, given the iked bypass [S1].
• Gap: the provided material does not state fixed versions.
• Gap: the roles of CVE-2024-26008 and CVE-2024-26009 are unexplained. One story calls CVE-2024-26008 a FortiJump alias, but SecurityWeek's linked content could not be read [S3].
• Gap: the sources do not say whether PEERSTITCH survives a reboot.

Detection coverage — checked automatically

Checked automatically 2026-11-01 15:13Z from public sources: 18 published, 27 nothing found, 0 not machine-checkable, 0 failed. "Nothing found" means the public source answered and had nothing, as of that moment; a feed covers only its newest posts. Re-checked daily.

Exposure queries — generated automatically

vuln:CVE-2024-47575

vuln:CVE-2024-26008

vuln:CVE-2025-61624

cpe:"cpe:/a:fortinet:fortimanager"

product:"Fortimanager"

host.services: (software.product = "Fortimanager")

cpe:"cpe:/a:fortinet:fortimanager_cloud"

product:"Fortimanager Cloud"

host.services: (software.product = "Fortimanager Cloud")

cpe:"cpe:/a:fortinet:fortiproxy"

product:"Fortiproxy"

host.services: (software.product = "Fortiproxy")

cpe:"cpe:/a:fortinet:fortiswitchmanager"

product:"Fortiswitchmanager"

host.services: (software.product = "Fortiswitchmanager")

http.title:"FortiManager"

http.title:"FortiProxy"

Internet-wide count, trend

Shodan's count of matching services on the whole internet, one point a day; the scope (your ranges) is never part of it. A count moves with Shodan's crawl as much as with patching, so read the direction, not the digit.

NVD names 2 more affected products (libraries and embedders); the CVE query covers them where Shodan has fingerprinted the version.

Banner spellings: a model read 5 from the NVD names and this card's text (former and marketing names, console titles); 2 matched something on Shodan and are shown above, the rest were dropped.

Scope every query in your own tool, never in a shared document: Shodan `net:<your_ranges>`, `org:"<your_org>"` or `hostname:<your_domain>` (or a Shodan Monitor network alert, which applies the scope for you); Censys `host.ip: <your_ranges>` or `host.dns.names: <your_domain>`. Then compare the banner version with the affected range. Generated automatically 2026-11-01 15:13Z from the CVE ids and NVD's CPE configurations, each Shodan query counted against Shodan itself; re-built daily with the coverage check.

Open questions

• Which, if any, is the role of CVE-2024-26008 and CVE-2024-26009? Its NVD CVSS of 5.3 sits poorly with the FortiJump alias claim.
• Do the '8550' and '169.254.0.1' markers in the pipeline's behavior notes come from Unit 42? The quoted sources do not state them.
• Does PEERSTITCH persist across reboot or firmware upgrade?
• Which versions fix CVE-2025-61624 per FG-IR-26-122?
• SecurityWeek's linked page returned unrelated content. Does it add anything once readable [S3]?
• The thread's dates are out of order: the 2026-10-16 story is flagged as today, but later-dated stories exist. Confirm the brief date.

Sources

• [S1] https://thehackernews.com/2026/10/attackers-exploit-fortios-flaw-to.html · The Hacker News
• [S2] https://fortiguard.fortinet.com/psirt/FG-IR-26-122 · FortiGuard Labs
• [S3] https://www.securityweek.com/exploited-fortinet-bug-linked-to-stealthy-fortigate-implant-in-telecom-hack/ · SecurityWeek
• [S4] https://www.cisa.gov/known-exploited-vulnerabilities-catalog · CISA
• [S5] https://www.cisa.gov/news-events/alerts/2026/10/16/cisa-adds-two-known-exploited-vulnerabilities-catalog · CISA

Public OSINT only. AI-generated by the pipeline; structure follows the DAIR model from Dynamic Incident Response (Joshua Wright). Published automatically once it crosses the publish bar.