Malicious PDF — malware analysis report

Static analysis result for SHA-256 d79241797f1344a1…

MALICIOUS

PDF

13.2 KB
MD5: 6425bfb900ca9a9cfac2f40de5f79798 SHA-1: b31bec7e94176c7dc264842d0b3215d6abb607d7 SHA-256: d79241797f1344a1346c74d09118a8b0b73b95ff571afbe226948555d7a23615
216 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link

The PDF file contains obfuscated JavaScript that is XOR-decoded and then executed. This JavaScript is designed to exploit the Collab.collectEmailInfo method in Adobe Reader, a known vulnerability (CVE-2007-5659). The primary function of the script is to download and execute a second-stage payload, indicated by the 'PDF_BINARY_XOR_JS_STAGER' and 'CVE_2007_5659' heuristic firings. The document body is heavily obfuscated and unreadable, providing no direct clues to the lure.

Heuristics 7

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • ClamAV: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
  • Binary-XOR JavaScript stager high PDF_BINARY_XOR_JS_STAGER
    PDF JavaScript stores viewer-version payload branches as long binary digit strings, XORs each bit pair, converts 8-bit chunks with String.fromCharCode, and evals the recovered exploit stage.
  • String.fromCharCode medium PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically (matched inside decoded stream)
  • Suspicious extracted artifact medium 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.
  • JavaScript action low 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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0049_000.js
4682c3159ccdbcde482271fbfcc1b98769b493acd300604c661ce924dec04fc6
pdf-javascript-stream PDF /JS object 49 at offset 0xA 78556 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 6 long base64-like blob(s).
binary_xor_stage_000.js
df4392da5ae75b6a53ee5813cb8c1a374e11da6cfd2c80dec2252b2f535f3c94
deobfuscated-js binary-XOR decoded JavaScript at offset 0x3F8 1312 bytes