Malicious PDF / .TXT — malware analysis report

Static analysis result for SHA-256 71f1cbad867a7a44…

MALICIOUS

PDF / .TXT

11.9 KB
MD5: 583a678a8d2dc449b8e9fe2716f19d18 SHA-1: c4b4957e43c432ac6142ebff032127e928b0d398 SHA-256: 71f1cbad867a7a44f5fe56ec6e132f4167bbd3e2b58dbfa3cc90b2b941773af9
370 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains obfuscated JavaScript that exploits CVE-2007-5659, specifically targeting Adobe Reader versions within a certain patch range. The script is designed to download a second-stage payload from the URL http://ujiaafwumlc.com/nte/PROX.html/eH79bb13eaV0100f060006R87006a76102T97ec0b77203l000c. This indicates a clear intent to execute arbitrary code from a remote source.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 10

  • 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)
  • Adobe Reader APSB08-13 patch-range version gate (CVE-2007-5659) high CVE likely PDF_JS_ADOBE_APSB08_13_PATCH_GATE
    PDF JavaScript gates the exploit payload on (>= 8 && < 8.1.1) OR (< 7.1) — the Reader 7.0.x / 8.0–8.1.1 window patched by Adobe APSB08-13 for the CVE-2007-5659 Collab.collectEmailInfo buffer overflow. Only kits that target that exact bug check both of those patch points; benign scripts do not.
  • Hex-obfuscated scripting name object critical PDF_OBFUSCATED_NAME_OBJECT
    A PDF name object that drives script execution (/JavaScript or /JS) is written with #XX hex escapes to hide it from string-based scanners — e.g. /J#61v#61S#63r#69p#74 decoding to /JavaScript. Legitimate PDF producers always write these names literally; hex-encoding an executable name is a deliberate evasion used by exploit-kit and dropper PDFs.
  • Annotation subject percent-decoding eval stager critical PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER
    OpenAction JavaScript forces annotation enumeration, reads an annotation /Subject payload with getAnnots(), rewrites marker bytes into percent escapes, decodes it with unescape(), and dispatches it through eval. This is a high-confidence exploit-kit staging pattern. It is intentionally not mapped to CVE-2009-1492 unless getAnnots() itself carries the crafted integer or long argument shape for that vulnerability.
  • ClamAV: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • 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://ujiaafwumlc.com/nte/PROX.html/eH79bb13eaV0100f060006R87006a76102T97ec0b77203l000c

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
6f60a1053baafdc578f85eae84a2dc6d16775fbd66240d82cbfb7b4f4ff4e90a
pdf-javascript-stream PDF /JS object 7 at offset 0x19D 295 bytes
legacy_pdfkit_stage_000.js
8c8677077b81766c140bf9c747161534726883a9cfc8ddd1b7eef87e817dcb48
deobfuscated-js z-percent hex-pair decoded JavaScript at offset 0x2E9 5006 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
5505c3c2638f78da3e1040fac79c403ca18630b18d18c67f0909c4d9d3157b01
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2E9 12070 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).