CVE-2008-2469

published 2008-10-23

CVE-2008-2469: Heap-based buffer overflow in the SPF_dns_resolv_lookup function in Spf_dns_resolv.c in libspf2 before 1.2.8 allows remote attackers to execute arbitrary code…

Priority P2 63 critical 10 CVSS 2.0

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

EXPLOIT

Heap-based buffer overflow in the SPF_dns_resolv_lookup function in Spf_dns_resolv.c in libspf2 before 1.2.8 allows remote attackers to execute arbitrary code via a long DNS TXT record with a modified length field.

Affected

14 ranges

Vendor	Product	Version range	Fixed in
debian	libspf2	< libspf2 1.2.9-1 (bookworm)	libspf2 1.2.9-1 (bookworm)
libspf	libspf2	<= 1.2.7	—
libspf	libspf2	—	—
libspf	libspf2	—	—
libspf	libspf2	—	—
libspf	libspf2	—	—
libspf	libspf2	—	—
libspf	libspf2	—	—
libspf	libspf2	—	—
libspf	libspf2	—	—
libspf2	libspf2	>= 0 < 1.2.9-1	1.2.9-1
libspf2	libspf2	>= 0 < 1.2.9-1	1.2.9-1
libspf2	libspf2	>= 0 < 1.2.9-1	1.2.9-1
libspf2	libspf2	>= 0 < 1.2.9-1	1.2.9-1

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

command ./spfquery -ip=1.2.3.4 [email protected]↗

bytes↗

substr($newans, 44, 1, pack('c',0xff))

• → Alert on DNS TXT responses containing a string-length prefix byte (0xFF) that exceeds the actual allocated buffer size (e.g., writing 255 bytes to a 15-byte buffer), as this is the direct trigger for the heap overflow in libspf2's SPF_dns_resolv_lookup. ↗
• → Monitor for DNS TXT responses to SPF queries where the inner string-length byte (second length field in the rdata stream) is not bounded by the outer rdlen field — specifically where `len = *src` yields a value larger than the remaining rdlen, indicating exploitation of the unbounded memcpy in Spf_dns_resolv.c. ↗
• → Flag DNS TXT responses for SPF-queried domains that include two TXT records: one legitimate 'v=spf1 mx +all' record and one anomalously long all-ASCII payload record (~233+ bytes), as this is the attack pattern used in the PoC. ↗

• · The vulnerability only affects libspf2 versions before 1.2.8; systems running 1.2.8 or later (e.g., Debian-packaged 1.2.9-1) are not affected. ↗
• · The attack is delivered via a rogue/attacker-controlled DNS server responding to SPF TXT lookups; the victim system must be querying DNS for SPF records (e.g., during mail processing) to be exposed. ↗

CVSS provenance

nvd v2.0 10.0 CRITICAL AV:N/AC:L/Au:N/C:C/I:C/A:C

osv 10.0 CRITICAL

vendor_debian 10.0 HIGH

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