CVE-2016-2385 : Détail

CVE-2016-2385

9.8
/
Critique
Overflow
24.86%V4
Network
2016-04-11
13h00 +00:00
2018-10-09
16h57 +00:00
CVE.org
NVD
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Descriptions du CVE

Heap-based buffer overflow in the encode_msg function in encode_msg.c in the SEAS module in Kamailio (formerly OpenSER and SER) before 4.3.5 allows remote attackers to cause a denial of service (memory corruption and process crash) or possibly execute arbitrary code via a large SIP packet.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.0 9.8 CRITICAL CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 nvd@nist.gov
V2 10 AV:N/AC:L/Au:N/C:C/I:C/A:C 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.

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.
EPSS First.org

Informations sur l'Exploit

Exploit Database EDB-ID : 39638

Date de publication : 2016-03-29 22h00 +00:00
Auteur : Stelios Tsampas
EDB Vérifié : No

census ID: census-2016-0009 CVE ID: CVE-2016-2385 Affected Products: Kamailio 4.3.4 (and possibly previous versions) Class: Heap-based Buffer Overflow (CWE-122) Remote: Yes Discovered by: Stelios Tsampas Kamailio (successor of former OpenSER and SER) is an Open Source SIP Server released under GPL, able to handle thousands of call setups per second. Kamailio can be used to build large platforms for VoIP and realtime communications, presence, WebRTC, Instant messaging and other applications. It can also easily be applied to scaling up SIP-to-PSTN gateways, PBX systems or media servers. There is a (remotely exploitable) heap overflow vulnerability in Kamailio version 4.3.4 and possibly in previous versions. The vulnerability takes place in the SEAS module, which enables Kamailio to transfer the execution logic control of a SIP message to a given external entity, called the Application Server. Details The heap overflow can be triggered if Kamailio is configured to use the SEAS module, more specifically if Kamailio calls the module’s single exported function as_relay_t(). The heap overflow is located in function encode_msg(), file encode_msg.c, line 269: int encode_msg(struct sip_msg *msg, char *payload,int len) { ... /*now we copy the actual message after the headers-meta-section*/ memcpy(&payload[j],msg->buf,msg->len); LM_DBG("msglen = %d,msg starts at %d\n",msg->len,j); j=htons(j); ... } msg is a pointer to a sip_msg structure and it is basically the current SIP packet being processed by Kamailio. msg->buf is a buffer which holds the packet's contents and msg->len is the packet's length. Unsurprisingly, msg->len can take arbitrary values (bound by the packet size) while j takes the value of 180 in most cases. The destination buffer payload is allocated in encoded_msg()'s caller function, create_as_event_t(), specifically in file seas.c, line 442: char * create_as_event_t(struct cell *t, struct sip_msg *msg, char processor_id, int *evt_len, int flags) { ... if(!(buffer=shm_malloc(ENCODED_MSG_SIZE))){ LM_ERR("Out Of Memory !!\n"); return 0; } ... if(encode_msg(msg,buffer+k,ENCODED_MSG_SIZE-k)<0){ LM_ERR("Unable to encode msg\n"); goto error; } ... } Preprocessor constant ENCODE_MSG_SIZE is defined as 3200 and variable k at line 521 holds the value 34. The problem is that the program does not check the packet's length if it is larger than the destination buffer. If a user makes a request with a large enough packet then the buffer will overflow. Discussion We were able to trigger the bug remotely using a large UDP packet. A proof-of-concept packet is provided below that crashes the Kamailio process handling the request. From bash the packet can be sent using the following command: cat seas-trigger.packet > /dev/udp/KAMAILIO-IP/KAMAILIO-PORT This bug may potentially provide attackers with remote code execution capabilities. Recommendation The security defect has been fixed in version 4.3.5 of Kamailio. Upgrading to the latest stable version is strongly advised. Disclosure Timeline Vendor Contact: February 12th, 2016 CVE assignment: February 15th, 2016 Vendor Patch Release: March 3rd, 2016 Public Advisory: March 30th, 2016 Proof of Concept: https://census-labs.com/media/seas-trigger.packet https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39638.zip

Products Mentioned

Configuraton 0

Debian>>Debian_linux >> Version 8.0

Configuraton 0

Kamailio>>Kamailio >> Version To (including) 4.3.4

Références

http://www.debian.org/security/2016/dsa-3535
Tags : vendor-advisory, x_refsource_DEBIAN
https://www.exploit-db.com/exploits/39638/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.debian.org/security/2016/dsa-3537
Tags : vendor-advisory, x_refsource_DEBIAN
Les informations affichées sur CVE Find proviennent de plusieurs sources de référence rigoureusement sélectionnées. Les données CVE sont fournies par MITRE Corporation et la National Vulnerability Database (NVD). Le catalogue des vulnérabilités activement exploitées (KEV) provient de la Cybersecurity and Infrastructure Security Agency (CISA), tandis que les scores EPSS sont issus de FIRST.org. Enfin, les données relatives aux faiblesses logicielles (CWE) et aux schémas d'attaque courants (CAPEC) sont maintenues par MITRE Corporation, et les informations sur les configurations logicielles et matérielles (CPE) proviennent du NVD.