akira

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The AKIRA ransomware appends the exact suffix .akira to each encrypted file.
  • Renaming Convention:
  • Original file sales_report_Q3.xlsx is transformed into sales_report_Q3.xlsx.akira.
  • In some observed strains, AKIRA will first add a hexadecimal “marker” before the final extension if the entire file has been overwritten (e.g., salary_ledger.csv.[BFBF0FDA].akira), but the fixed .akira tail always remains.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
  • First public sighting: mid-March 2023 (initial posts on ID-Ransomware, social media reports).
  • Major spike: May-June 2023, coinciding with a large-scale double-extortion campaign targeting VPN appliances, educational institutions, and medium-size enterprises.
  • Ongoing activity: Weekly new victim leaks on the Akira dark-web blog still appearing through at least October 2023.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Exploitation of CVE-2020-3258 / CVE-2023-20269 (Cisco ASA & AnyConnect) – used to gain initial foothold via external-facing VPN concentrators lacking the August 2023 Cisco patch.
  2. Weak or reused RDP passwords – brute-forced over the Internet or after credential dumps from prior breaches.
  3. Phishing attachments – macro-laced Office docs or RAR archives delivering Cobalt Strike beacon for manual post-exploitation.
  4. Living-off-the-land tooling – abuses net.exe, wmic, vssadmin, bcdedit, WMIC remote process calls to laterally move before pushing the ransomware binary.

Remediation & Recovery Strategies:

1. Prevention

  • VPN hardening: Patch Cisco ASA, FTD, AnyConnect appliance to the latest interim release (target builds 9.18.2.x or 9.19.1.x) that remediate CVE-2023-20269.
  • MFA everywhere: Enforce multi-factor authentication for all VPN, RDP, and privileged accounts.
  • Network segmentation: Isolate management VLANs, disable RDP from the Internet, restrict port 443/4433 on Cisco VPN clusters to known source IPs.
  • Backups: Follow 3-2-1 rule (3 copies, 2 different media, 1 off-line/air-gapped). Test restore. Ensure immutable storage (e.g., Veeam Hardened Repository, AWS Object Lock) to thwart VSS/wmic deletion.

2. Removal

Step-by-step Containment & Cleanup:

  1. Power-off and isolate infected hosts (pull network cable or disable switchport), but do NOT restart—AKIRA wipes shadow copies at boot time if it hasn’t yet.
  2. Snapshot/image disk/drive for forensics (DD/E01 image) before remediation—keeps evidence in case a decryption breakthrough appears later.
  3. Boot from clean rescue media (Windows PE/Linux Live USB).
  4. Terminate malicious processes & services identified via Autoruns, Process Explorer. File names often start with srvhost*.exe, akira.exe, or are in %AppData%.
  5. Delete persistence keys:
  • Run reg delete "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" /v <random_value> if present.
  1. Full AV scan: Use updated Microsoft Defender (engine 1.395.x+) or ESET/Rapid7 to quaranteen dropper and beacon remnants.
  2. Patch or OS reinstall – Do a clean reinstall or in-place repair on AD controllers and file shares to evict residual backdoors.

3. File Decryption & Recovery

  • Current Status: AKIRA employs Curve25519 + ChaCha20-Poly1305 encryption; private keys are held solely by the attackers.
  • Decryption feasibility today: No free decryptor is available. Any publicly-surfaced “.akira_unpacker” tools are fake—AVOID.
  • Partial recovery avenues:
  • Check backups → Restore from clean, offline backup.
  • Volume Shadow Copy → Verify with vssadmin list shadows or ShadowExplorer, but expect them deleted in most attacks.
  • File repair → ZIP/JPG/PDF with partial corruption can sometimes be carved; use PhotoRec or DiskDigger on the image taken in step 2.
  • Negotiation/leak offsets → Note that AKIRA publishes “proof-of-theft” on leak site; weigh legal & PR risks if contemplating payment.

4. Other Critical Information

  • Credential-stuffing twist: In July 2023 some variants started renaming the domain controller filenames to highlight previous compromised credentials (username/password combos pasted as prepended text), increasing psychological pressure.
  • Cross-platform variant: As of October 2023, a Linux/ ESXi locker binary (akira_esx) appeared that targets /vmfs/volumes; the same .akira extension but leaves a ransom note labeled akira_linux.tor_readme.txt.
  • End-to-end enterprise wipe: In addition to encrypting, AKIRA deletes 450+ services (Exchange, SQL, Oracle, Veeam) prior to encryption to prevent recovery tools from running—reboot after infection without isolating will usually fail to boot.
  • OSCP-certified actors: Forensics show attackers passing OSCP lab-style enumeration scripts (kerberoast.bat) indicating a financially motivated yet skilled red-team background.

Bottom line: There is no technical decryption path yet for .akira victims—validated offline backups and swift network isolation remain the only reliable recovery methods.