This is a working proof-of-concept exploit for CVE-2022-26531, targeting a format string vulnerability in the zysh binary on Zyxel devices. It leverages the 'ping' command to overwrite the GOT entry of fork() with a shellcode address, achieving remote code execution.
Classification
Working Poc 100%
Target:
Zyxel USG/ZyWALL series firmware versions 4.09 through 4.71, USG FLEX series firmware versions 4.50 through 5.21, ATP series firmware versions 4.32 through 5.21, VPN series firmware versions 4.30 through 5.21, NSG series firmware versions 1.00 through 1.33 Patch 4, NXC2500 firmware version 6.10(AAIG.3) and earlier versions, NAP203 firmware version 6.25(ABFA.7) and earlier versions, NWA50AX firmware version 6.25(ABYW.5) and earlier versions, WAC500 firmware version 6.30(ABVS.2) and earlier versions, and WAX510D firmware version 6.30(ABTF.2) and earlier versions
Auth required
Prerequisites:
Authenticated access to the zysh shell · SSH access to the target device