Bugzilla – Bug 1174635
VUL-0: CVE-2020-14345: xorg-x11-server: Out-Of-Bounds Access Privilege Escalation Vulnerability (ZDI-CAN-11428)
Last modified: 2020-08-31 04:18:20 UTC
-- CVSS ----------------------------------------- 7.8: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -- ABSTRACT ------------------------------------- Trend Micro's Zero Day Initiative has identified a vulnerability affecting the following products: X.Org - Server -- VULNERABILITY DETAILS ------------------------ * Version tested:1.20.4 * Installer file:debian-10.4.0-amd64-xfce-CD-1.iso * Platform tested:debian 10.4.0 amd64 desktop --- ### Analysis ``` the exploit doesn't work if the OS installed on vmware and default virtualbox it works on virtualbox with VBoxVGA graphic controller the request handler, ProcXkbSetNames, in x11 server did not validate the request length before accessing https://github.com/freedesktop/xorg-xserver/blob/master/xkb/xkb.c#L4348 exploit use pixmap to spray and achieve the arbitrary read/write it leads to LPE for some distribution (xorg in debian is run a root) and RCE for ssh x11 forwarding environmnet ``` ~~~C++ int ProcXkbSetNames(ClientPtr client) { CARD32 *tmp; REQUEST(xkbSetNamesReq); REQUEST_AT_LEAST_SIZE(xkbSetNamesReq); ... /* check device-independent stuff */ tmp = (CARD32 *) &stuff[1];<-- (1) points to next CARD32 without checking the enough size, it can then points OOB ... /* start of device-dependent tests */ rc = _XkbSetNamesCheck(client, dev, stuff, tmp);<-- (2) ... } static int _XkbSetNamesCheck(ClientPtr client, DeviceIntPtr dev, xkbSetNamesReq * stuff, CARD32 *data) { ... tmp = data; ... if ((stuff->which & XkbKeyAliasesMask) && (stuff->nKeyAliases > 0)) { tmp += stuff->nKeyAliases * 2;<-- (3) } if (stuff->which & XkbRGNamesMask) { if (stuff->nRadioGroups < 1) { client->errorValue = _XkbErrCode2(0x0d, stuff->nRadioGroups); return BadValue; } tmp = _XkbCheckAtoms(tmp, stuff->nRadioGroups, client->swapped, &bad);<-- (4) if (!tmp) { client->errorValue = bad; return BadAtom; } } ... } static CARD32 * _XkbCheckAtoms(CARD32 *wire, int nAtoms, int swapped, Atom *pError) { register int i; for (i = 0; i < nAtoms; i++, wire++) { if (swapped) { swapl(wire);<-- (5) swap bytes out-of-bounds } ... } return wire; } ~~~ debug log ``` (gdb) b *0x15D3DB+0x55932d486000 Breakpoint 1 at 0x55932d5e33db (gdb) c Continuing. Thread 1 "Xorg" hit Breakpoint 1, 0x000055932d5e33db in ?? () (gdb) x/i $pc => 0x55932d5e33db:lea r14,[r13+0x1c]// tmp = (CARD32 *) &stuff[1]; // now, r14 is OOB and points to next request (gdb) x/10xg $r13 0x55932ea64010:0x00000100000712870x0000000000002400// xkbSetNamesReq, len = 0x1c 0x55932ea64020:0x00000100000000000x0400001000000001 // xInternAtomReq, len = 0x8 0x55932ea64030:0x33323130000008000x7b3f22b900363534 // char*, len = 0x7 0x55932ea64040:0x000100855ba152030x0000000100020087 0x55932ea64050:0x00000000000000000x0000000000000000 (gdb) x/s 0x55932ea64034 0x55932ea64034:"0123456" (gdb) awatch *0x55932ea64034 Hardware access (read/write) watchpoint 2: *0x55932ea64034 (gdb) c Continuing. Thread 1 "Xorg" hit Hardware access (read/write) watchpoint 2: *0x55932ea64034 Value = 858927408 0x000055932d5d90d3 in ?? () (gdb) x/20i $pc-0x10 0x55932d5d90c3:add BYTE PTR [rax],0x0 0x55932d5d90c6:add BYTE PTR [rax],al 0x55932d5d90c8:add rbx,0x4 0x55932d5d90cc:cmp rbp,rbx 0x55932d5d90cf:je 0x55932d5d90f1 0x55932d5d90d1:mov edi,DWORD PTR [rbx]// OOBR => 0x55932d5d90d3:test r12d,r12d 0x55932d5d90d6:je 0x55932d5d90dc 0x55932d5d90d8:bswap edi 0x55932d5d90da:mov DWORD PTR [rbx],edi// OOBW 0x55932d5d90dc:test edi,edi 0x55932d5d90de:je 0x55932d5d90c8 0x55932d5d90e0:call 0x55932d4ce980 <ValidAtom> 0x55932d5d90e5:test eax,eax 0x55932d5d90e7:jne 0x55932d5d90c8 0x55932d5d90e9:mov eax,DWORD PTR [rbx] 0x55932d5d90eb:xor ebp,ebp 0x55932d5d90ed:mov DWORD PTR [r13+0x0],eax 0x55932d5d90f1:add rsp,0x8 0x55932d5d90f5:mov rax,rbp (gdb) c Thread 1 "Xorg" hit Hardware access (read/write) watchpoint 2: *0x55932ea64034 Old value = 858927408 New value = 808530483 0x000055932d5d90dc in ?? () (gdb) x/s 0x55932ea64034 0x55932ea64034:"3210456"// byte is swapped (gdb) x/10i $pc-0x10 0x55932d5d90cc:cmp rbp,rbx 0x55932d5d90cf:je 0x55932d5d90f1 0x55932d5d90d1:mov edi,DWORD PTR [rbx] 0x55932d5d90d3:test r12d,r12d 0x55932d5d90d6:je 0x55932d5d90dc 0x55932d5d90d8:bswap edi 0x55932d5d90da:mov DWORD PTR [rbx],edi => 0x55932d5d90dc:test edi,edi 0x55932d5d90de:je 0x55932d5d90c8 0x55932d5d90e0:call 0x55932d4ce980 <ValidAtom> (gdb) bt #0 0x000055932d5d90dc in ?? () #1 0x000055932d5de551 in ?? () #2 0x000055932d5e3448 in ?? () #3 0x000055932d4e096e in ?? () #4 0x000055932d4e4916 in ?? () #5 0x00007fe82c49f09b in __libc_start_main (main=0x55932d4ce640, argc=10, argv=0x7fff872eee28, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff872eee18) at ../csu/libc-start.c:308 #6 0x000055932d4ce67a in _start () (gdb) ``` -- CREDIT --------------------------------------- This vulnerability was discovered by: Jan-Niklas Sohn working with Trend Micro Zero Day Initiative -- FURTHER DETAILS ------------------------------ If supporting files were contained with this report they are provided within a password protected ZIP file. The password is the ZDI candidate number in the form: ZDI-CAN-XXXX where XXXX is the ID number. Please confirm receipt of this report. We expect all vendors to remediate ZDI vulnerabilities within 120 days of the reported date. If you are ready to release a patch at any point leading up to the deadline, please coordinate with us so that we may release our advisory detailing the issue. If the 120-day deadline is reached and no patch has been made available we will release a limited public advisory with our own mitigations, so that the public can protect themselves in the absence of a patch. Please keep us updated regarding the status of this issue and feel free to contact us at any time: Zero Day Initiative zdi-disclosures@trendmicro.com The PGP key used for all ZDI vendor communications is available from: http://www.zerodayinitiative.com/documents/disclosures-pgp-key.asc -- INFORMATION ABOUT THE ZDI -------------------- Established by TippingPoint and acquired by Trend Micro, the Zero Day Initiative (ZDI) neither re-sells vulnerability details nor exploit code. Instead, upon notifying the affected product vendor, the ZDI provides its Trend Micro TippingPoint customers with zero day protection through its intrusion prevention technology. Explicit details regarding the specifics of the vulnerability are not exposed to any parties until an official vendor patch is publicly available. Please contact us for further details or refer to: http://www.zerodayinitiative.com -- DISCLOSURE POLICY ---------------------------- Our vulnerability disclosure policy is available online at: http://www.zerodayinitiative.com/advisories/disclosure_policy/ TREND MICRO EMAIL NOTICE The information contained in this email and any attachments is confidential and may be subject to copyright or other intellectual property protection. If you are not the intended recipient, you are not authorized to use or disclose this information, and we request that you notify us by reply mail or telephone and delete the original message from your mail system. 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All supported code streams appear to be affected.
Date: Tue, 25 Aug 2020 17:24:05 +0200 From: Matthieu Herrb <matthieu@herrb.eu> To: xorg-announce@lists.x.org Subject: X.Org server security advisory: August 25, 2020 Multiple input validation failures in X server extensions ========================================================= All theses issuses can lead to local privileges elevation on systems where the X server is running privileged. * CVE-2020-14345 / ZDI CAN 11428 XkbSetNames Out-Of-Bounds Access The handler for the XkbSetNames request does not validate the request length before accessing its contents. * CVE-2020-14346 / ZDI CAN 11429 XIChangeHierarchy Integer Underflow An integer underflow exists in the handler for the XIChangeHierarchy request. * CVE-2020-14361 / ZDI CAN 11573 XkbSelectEvents Integer Underflow An integer underflow exist in the handler for the XkbSelectEvents request. * CVE-2020-1436 / ZDI CAN 11574 XRecordRegisterClients Integer Underflow An integer underflow exist in the handler for the CreateRegister request of the X record extension. Patches ------- Patches for this issues have been commited to the xorg server git repository. xorg-server 1.20.9 will be released shortly and will include these patches. https://gitlab.freedesktop.org/xorg/xserver.git commit 11f22a3bf694d7061d552c99898d843bcdaf0cf1 Correct bounds checking in XkbSetNames() CVE-2020-14345 / ZDI 11428 commit 1e3392b07923987c6c9d09cf75b24f397b59bd5e Fix XIChangeHierarchy() integer underflow CVE-2020-14346 / ZDI-CAN-11429 commit 90304b3c2018a6b8f4a79de86364d2af15cb9ad8 Fix XkbSelectEvents() integer underflow CVE-2020-14361 ZDI-CAN 11573 commit 24acad216aa0fc2ac451c67b2b86db057a032050 Fix XRecordRegisterClients() Integer underflow CVE-2020-14362 ZDI-CAN-11574 Thanks ====== These vulnerabilities have beend discovered by Jan-Niklas Sohn working with Trend Micro Zero Day Initiative. -- Matthieu Herrb
This is an autogenerated message for OBS integration: This bug (1174635) was mentioned in https://build.opensuse.org/request/show/829591 Factory / xorg-x11-server
Packages are submitted (factory/TW, sle15-sp2, sle15-sp1, sle15, sle12-sp5, sle12-sp4, sle12-sp2, sle11-sp3, sle11-sp1). Reassigning back to security team.
SUSE-SU-2020:2242-1: An update that fixes three vulnerabilities is now available. Category: security (important) Bug References: 1174633,1174635,1174638 CVE References: CVE-2020-14345,CVE-2020-14346,CVE-2020-14347 JIRA References: Sources used: SUSE Linux Enterprise Software Development Kit 12-SP5 (src): xorg-x11-server-1.19.6-10.8.1 SUSE Linux Enterprise Server 12-SP5 (src): xorg-x11-server-1.19.6-10.8.1 NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
SUSE-SU-2020:14463-1: An update that fixes two vulnerabilities is now available. Category: security (important) Bug References: 1174633,1174635 CVE References: CVE-2020-14345,CVE-2020-14347 JIRA References: Sources used: SUSE Linux Enterprise Server 11-SP4-LTSS (src): xorg-x11-server-7.4-27.122.26.1 SUSE Linux Enterprise Point of Sale 11-SP3 (src): xorg-x11-server-7.4-27.122.26.1 SUSE Linux Enterprise Debuginfo 11-SP4 (src): xorg-x11-server-7.4-27.122.26.1 SUSE Linux Enterprise Debuginfo 11-SP3 (src): xorg-x11-server-7.4-27.122.26.1 NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
SUSE-SU-2020:2325-1: An update that fixes three vulnerabilities is now available. Category: security (important) Bug References: 1174633,1174635,1174638 CVE References: CVE-2020-14345,CVE-2020-14346,CVE-2020-14347 JIRA References: Sources used: SUSE OpenStack Cloud Crowbar 9 (src): xorg-x11-server-1.19.6-4.8.1 SUSE OpenStack Cloud 9 (src): xorg-x11-server-1.19.6-4.8.1 SUSE Linux Enterprise Server for SAP 12-SP4 (src): xorg-x11-server-1.19.6-4.8.1 SUSE Linux Enterprise Server 12-SP4-LTSS (src): xorg-x11-server-1.19.6-4.8.1 NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
SUSE-SU-2020:2240-1: An update that fixes three vulnerabilities is now available. Category: security (important) Bug References: 1174633,1174635,1174638 CVE References: CVE-2020-14345,CVE-2020-14346,CVE-2020-14347 JIRA References: Sources used: SUSE Linux Enterprise Workstation Extension 15-SP2 (src): xorg-x11-server-1.20.3-22.5.1 SUSE Linux Enterprise Module for Development Tools 15-SP2 (src): xorg-x11-server-1.20.3-22.5.1 SUSE Linux Enterprise Module for Basesystem 15-SP2 (src): xorg-x11-server-1.20.3-22.5.1 NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
SUSE-SU-2020:2326-1: An update that solves three vulnerabilities and has one errata is now available. Category: security (important) Bug References: 1120999,1174633,1174635,1174638 CVE References: CVE-2020-14345,CVE-2020-14346,CVE-2020-14347 JIRA References: Sources used: SUSE Linux Enterprise Server for SAP 15 (src): xorg-x11-server-1.19.6-8.16.1 SUSE Linux Enterprise Server 15-LTSS (src): xorg-x11-server-1.19.6-8.16.1 SUSE Linux Enterprise High Performance Computing 15-LTSS (src): xorg-x11-server-1.19.6-8.16.1 SUSE Linux Enterprise High Performance Computing 15-ESPOS (src): xorg-x11-server-1.19.6-8.16.1 NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
SUSE-SU-2020:2241-1: An update that fixes three vulnerabilities is now available. Category: security (important) Bug References: 1174633,1174635,1174638 CVE References: CVE-2020-14345,CVE-2020-14346,CVE-2020-14347 JIRA References: Sources used: SUSE Linux Enterprise Workstation Extension 15-SP1 (src): xorg-x11-server-1.20.3-14.5.1 SUSE Linux Enterprise Module for Development Tools 15-SP1 (src): xorg-x11-server-1.20.3-14.5.1 SUSE Linux Enterprise Module for Basesystem 15-SP1 (src): xorg-x11-server-1.20.3-14.5.1 NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
SUSE-SU-2020:2331-1: An update that fixes three vulnerabilities is now available. Category: security (moderate) Bug References: 1174633,1174635,1174638 CVE References: CVE-2020-14345,CVE-2020-14346,CVE-2020-14347 JIRA References: Sources used: SUSE OpenStack Cloud Crowbar 8 (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE OpenStack Cloud 8 (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE OpenStack Cloud 7 (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE Linux Enterprise Server for SAP 12-SP3 (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE Linux Enterprise Server for SAP 12-SP2 (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE Linux Enterprise Server 12-SP3-LTSS (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE Linux Enterprise Server 12-SP3-BCL (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE Linux Enterprise Server 12-SP2-LTSS (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE Linux Enterprise Server 12-SP2-BCL (src): xorg-x11-server-7.6_1.18.3-76.26.1 SUSE Enterprise Storage 5 (src): xorg-x11-server-7.6_1.18.3-76.26.1 HPE Helion Openstack 8 (src): xorg-x11-server-7.6_1.18.3-76.26.1 NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
Done
openSUSE-SU-2020:1279-1: An update that fixes three vulnerabilities is now available. Category: security (important) Bug References: 1174633,1174635,1174638 CVE References: CVE-2020-14345,CVE-2020-14346,CVE-2020-14347 JIRA References: Sources used: openSUSE Leap 15.1 (src): xorg-x11-server-1.20.3-lp151.4.3.1
openSUSE-SU-2020:1302-1: An update that fixes three vulnerabilities is now available. Category: security (important) Bug References: 1174633,1174635,1174638 CVE References: CVE-2020-14345,CVE-2020-14346,CVE-2020-14347 JIRA References: Sources used: openSUSE Leap 15.2 (src): xorg-x11-server-1.20.3-lp152.8.3.1