Malicious PDF — malware analysis report

Static analysis result for SHA-256 43de2723a4f339a2…

MALICIOUS

PDF

13.5 KB
MD5: aa253b67a1b7bb7319fb9b5d1019486c SHA-1: 45a9956a056be5b632b5db387e50859869127da3 SHA-256: 43de2723a4f339a29fb4a8c4c68c214e6df5981a0f2ce20022e58aa0c2d1b37f
186 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 script exploits CVE-2007-5659, a known vulnerability in Adobe Reader related to the Collab.collectEmailInfo method. The script's primary function is to download and execute a second-stage payload, indicated by the 'PDF_BINARY_XOR_JS_STAGER' and 'CVE_2007_5659' heuristic firings. The 'CLAMAV_DETECTION' and 'PDF_ObfuscatedNameObject' heuristics further confirm its malicious nature.

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.
  • 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • 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
javascript_obj0049_000.js
3c17c1e17e95bfe0784826cc68364fd330188a024782b41e24f799638f5eb303
pdf-javascript-stream PDF /JS object 49 at offset 0xA 80392 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
b0a18414eba3e6216ad778186dc24b159a562e1f2280f50da4151acf5221d862
deobfuscated-js binary-XOR decoded JavaScript at offset 0x464 1348 bytes