cbcvebase.
CVE-2002-0079
published 2002-04-22

CVE-2002-0079: Buffer overflow in the chunked encoding transfer mechanism in Internet Information Server (IIS) 4.0 and 5.0 Active Server Pages allows attackers to cause a…

PriorityP347high7.5CVSS 2.0
AVNACLAuNCPIPAP
EXPLOIT
EPSS
71.19%
99.3th percentile
Buffer overflow in the chunked encoding transfer mechanism in Internet Information Server (IIS) 4.0 and 5.0 Active Server Pages allows attackers to cause a denial of service or execute arbitrary code.

Affected

3 ranges
VendorProductVersion rangeFixed in
ciscoproducts_ms02-018
microsoftinternet_information_server
microsoftinternet_information_services

Detection & IOCsextracted from sources · hover to see the quote

path/iisstart.asp
commandPOST <path>?<buf> HTTP/1.0 Content-Type: application/x-www-form-urlencoded Transfer-Encoding: chunked 10 ABCDEFGHIJKLMNOP 4 XXXX 4 YYYY 0
bytes
\xeb\x02\xeb\x05\xe8\xf9\xff\xff\xff\x58\x83\xc0\x1d\x8d\xa0\xf0
bytes
\xeb\x18\x5f\x57\x5e\x33\xc9\xac\x3a\xc1\x74\x13\x3c\x30\x74\x05
  • Alert on HTTP POST requests targeting /iisstart.asp (or other .asp files) with both 'Transfer-Encoding: chunked' and an abnormally large query string, as the default IIS 5.0 script is explicitly called out as exploitable.
  • Look for chunked HTTP POST bodies containing multiple small fixed-size chunks (e.g., '10', '4', '4', '0') immediately followed by terminator '0\r\n\r\n' — this is the characteristic exploit request structure across all three exploit variants.
  • The exploit overwrites a top-level exception handler (SEH) at 0x77eaf44c and uses a direct jump payload at 0x0045C560 on unpatched IIS 5.0 — these hardcoded addresses can be used as memory forensic indicators on compromised Windows 2000 systems.
  • The exploit shellcode establishes a reverse/back-channel connection — monitor for unexpected outbound connections from the IIS worker process (inetinfo.exe / w3wp.exe) to external hosts, particularly on port 25.
  • Exploit variant 3 brute-forces return addresses in the range 0x00400000–0x00500000 and binds a shell on port 7788 — scan for unexpected listeners on port 7788 post-exploitation.
  • ·The hardcoded RET address (0x0045C560) and SEH overwrite address (0x77eaf44c) are specific to unpatched Windows 2000 / IIS 5.0 Chinese or Japanese versions; they will differ across OS versions, service packs, and locales.
  • ·Exploit 1 (21368) was tested specifically on Windows 2000 Chinese Version with IIS 5.0 unpatched; the srcdata and jmpaddr constants (0x01e2fb1c, 0x00457494) are version-specific and may not apply to other builds.
  • ·Cisco products are affected only because they run on top of vulnerable IIS installations — the vulnerability is in IIS itself, not in the Cisco software, so patching IIS resolves the exposure for Cisco products as well.
CVEs like this are exactly what “Exploited This Week” covers.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.