CVE-2006-3440

published 2006-08-09

CVE-2006-3440: Buffer overflow in the Winsock API in Microsoft Windows 2000 SP4, XP SP1 and SP2, and Server 2003 SP1 allows remote attackers to execute arbitrary code via…

Priority P2 64 critical 10 CVSS 2.0

AV N AC L Au N C C I C A C

EXPLOIT

Buffer overflow in the Winsock API in Microsoft Windows 2000 SP4, XP SP1 and SP2, and Server 2003 SP1 allows remote attackers to execute arbitrary code via unknown vectors, aka "Winsock Hostname Vulnerability."

Affected

2 ranges

Vendor	Product	Version range	Fixed in
microsoft	windows_2003_server	—	—
microsoft	windows_2003_server	—	—

Detection & IOCs extracted from sources · hover to see the quote

port 53/UDP↗

process services.exe↗

bytes↗

\x85\x80 (DNS Flags field in malicious response)

bytes↗

\x08\x50\x52\x4f\x54\x4f\x43\x4f\x4c (TXT RDATA: PROTOCOL) with zero-length follow-on RDATA fields

• → Monitor for services.exe crashing following DNS hostname resolution activity — this is the primary crash indicator for CVE-2006-3440 exploitation. ↗
• → Detect malicious DNS responses containing a TXT record with zero-length RDATA fields immediately following a non-zero-length RDATA string — this is the malformed structure that triggers the Winsock buffer overflow. ↗
• → Detect DNS responses with both an A record and a TXT record in the ANSWER section (Answer RR count = 0x0002) combined with an Authority RR, sent over UDP port 53 — characteristic of the PoC exploit packet structure. ↗
• → Flag DNS responses where the DNS flags field is 0x8580 (Response, Authoritative, Recursion Desired, Recursion Available) — this non-standard flag combination is used by the exploit's rogue DNS server. ↗

• · The exploit may require multiple attempts before triggering the crash in services.exe — a single malformed DNS response may not be sufficient. ↗
• · This PoC only demonstrates a Denial of Service (crash of services.exe); the NVD advisory notes the actual vulnerability allows remote code execution via unknown vectors beyond what the PoC demonstrates. ↗

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