Cryptographic Issues Affecting showdoc/showdoc package, versions <2.9.13
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PHP-SHOWDOCSHOWDOC-1933448
- published1 Dec 2021
- disclosed1 Dec 2021
- credithi-unc1e
Introduced: 1 Dec 2021
CVE-2021-3990 (opens in a new tab)How to fix?
Upgrade showdoc/showdoc to version 2.9.13 or higher.
Overview
showdoc/showdoc is a tool for an IT team to share documents online.
Affected versions of this package are vulnerable to Cryptographic Issues due to using cryptographically weak Pseudo-Random Number Generator (PRNG), logged in by LDAP will lead to a weak-password initialization.
##POC:
if ($ldap_user == $username) {$userInfo = D("User")->isExist($username) ; if(!$userInfo){ D("User")->register($ldap_user,$ldap_user.time()); //【register with a weak password, such as : tom/tom1637248826】 } $rs2=ldap_bind($ldap_conn, $dn , $password);//【when the LDAP password is WRONG，no password change will be implemented】 if ($rs2) { D("User")->updatePwd($userInfo['uid'], $password); return $this->checkLogin($username,$password); } } }
If there is a valid LDAP user , let's say named
tom, once he activated his account( such as logged with a WRONG password: suchtom/123456)Then, a record will be add to the Database ( by
D("User ")->register($ldap_user,$ldap_user.time());),with a password liketom1637248826, but the change of passwordD("User")->updatePwd($won't workBecause we all know that the password is like
tom.time(), andtime()is one kind of pseudo-random number, we could easily use brute force tool (such as Burp Intruder) to got it.Thus in this situation, an attacker could brute force the password of
tom's, until getting the password oftom1637248826