CVE-2017-7407 (published 2017-04-03T20:59Z)

The ourWriteOut function in tool_writeout.c in curl 7.53.1 might allow physically proximate attackers to obtain sensitive information from process memory in opportunistic circumstances by reading a workstation screen during use of a --write-out argument ending in a '%' character, which leads to a heap-based buffer over-read.

Severity: LOW
CVSS v2 base score: 2.1 (AV:L/AC:L/Au:N/C:P/I:N/A:N)
CVSS v3 base score: 2.4, LOW (CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)

Weakness information:
cwe_id: CWE-119
cwe_name: Improper Restriction of Operations within the Bounds of a Memory Buffer
description: 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.
extended_description: 
            Certain languages allow direct addressing of memory locations and do not automatically ensure that these locations are valid for the memory buffer that is being referenced. This can cause read or write operations to be performed on memory locations that may be associated with other variables, data structures, or internal program data.
         
         

Fix information:
repo_url: https://github.com/curl/curl
commit_details: repo_url: https://github.com/curl/curl
author: Dan Fandrich
author_date: 2017-03-11 10:59:34+01:00
msg: tool_writeout: fixed a buffer read overrun on --write-out

If a % ended the statement, the string's trailing NUL would be skipped
and memory past the end of the buffer would be accessed and potentially
displayed as part of the --write-out output. Added tests 1440 and 1441
to check for this kind of condition.

Reported-by: Brian Carpenter
repository: repo_url: https://github.com/curl/curl
repo_name: curl/curl
description: A command line tool and library for transferring data with URL syntax, supporting DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPS, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET, TFTP, WS and WSS. libcurl offers a myriad of powerful features
repo_language: C
owner: curl
file_changes: filename: tool_writeout.c
change_type: ModificationType.MODIFY
diff: @@ -113,7 +113,7 @@ void ourWriteOut(CURL *curl, struct OutStruct *outs, const char *writeinfo)
   double doubleinfo;
 
   while(ptr && *ptr) {
-    if('%' == *ptr) {
+    if('%' == *ptr && ptr[1]) {
       if('%' == ptr[1]) {
         /* an escaped %-letter */
         fputc('%', stream);

programming_language: C
filename: Makefile.inc
change_type: ModificationType.MODIFY
diff: @@ -153,7 +153,7 @@ test1408 test1409 test1410 test1411 test1412 test1413 test1414 test1415 \
 test1416 test1417 test1418 test1419 test1420 test1421 test1422 test1423 \
 test1424 \
 test1428 test1429 test1430 test1431 test1432 test1433 test1434 test1435 \
-test1436 test1437 test1438 test1439 \
+test1436 test1437 test1438 test1439 test1440 test1441 \
 \
 test1500 test1501 test1502 test1503 test1504 test1505 test1506 test1507 \
 test1508 test1509 test1510 test1511 test1512 test1513 test1514 test1515 \

programming_language: Shell
filename: test1440
change_type: ModificationType.ADD
diff: @@ -0,0 +1,31 @@
+<testcase>
+<info>
+<keywords>
+--write-out
+</keywords>
+</info>
+# Server-side
+<reply>
+</reply>
+
+# Client-side
+<client>
+<server>
+file
+</server>
+
+<name>
+Check --write-out with trailing %{
+</name>
+<command>
+file://localhost/%PWD/log/ --write-out '%{'
+</command>
+</client>
+
+# Verify data
+<verify>
+<stdout nonewline="yes">
+%{
+</stdout>
+</verify>
+</testcase>

programming_language: Markdown
filename: test1441
change_type: ModificationType.ADD
diff: @@ -0,0 +1,31 @@
+<testcase>
+<info>
+<keywords>
+--write-out
+</keywords>
+</info>
+# Server-side
+<reply>
+</reply>
+
+# Client-side
+<client>
+<server>
+file
+</server>
+
+<name>
+Check --write-out with trailing %
+</name>
+<command>
+file://localhost/%PWD/log/ --write-out '%'
+</command>
+</client>
+
+# Verify data
+<verify>
+<stdout nonewline="yes">
+%
+</stdout>
+</verify>
+</testcase>

programming_language: Markdown