Buffer Overflow Affecting openssl package, versions <1.1.1l-1ubuntu1


Severity

Recommended
high

Based on Ubuntu security rating

    Threat Intelligence

    EPSS
    6.79% (95th percentile)

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  • Snyk ID SNYK-UBUNTU2204-OPENSSL-2775627
  • published 25 Aug 2021
  • disclosed 24 Aug 2021

How to fix?

Upgrade Ubuntu:22.04 openssl to version 1.1.1l-1ubuntu1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl package and not the openssl package as distributed by Ubuntu. See How to fix? for Ubuntu:22.04 relevant fixed versions and status.

In order to decrypt SM2 encrypted data an application is expected to call the API function EVP_PKEY_decrypt(). Typically an application will call this function twice. The first time, on entry, the "out" parameter can be NULL and, on exit, the "outlen" parameter is populated with the buffer size required to hold the decrypted plaintext. The application can then allocate a sufficiently sized buffer and call EVP_PKEY_decrypt() again, but this time passing a non-NULL value for the "out" parameter. A bug in the implementation of the SM2 decryption code means that the calculation of the buffer size required to hold the plaintext returned by the first call to EVP_PKEY_decrypt() can be smaller than the actual size required by the second call. This can lead to a buffer overflow when EVP_PKEY_decrypt() is called by the application a second time with a buffer that is too small. A malicious attacker who is able present SM2 content for decryption to an application could cause attacker chosen data to overflow the buffer by up to a maximum of 62 bytes altering the contents of other data held after the buffer, possibly changing application behaviour or causing the application to crash. The location of the buffer is application dependent but is typically heap allocated. Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k).

References

CVSS Scores

version 3.1
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NVD

9.8 critical
  • Attack Vector (AV)
    Network
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    None
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    High
  • Availability (A)
    High
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SUSE

9.8 critical
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Red Hat

9.8 critical