Malicious PDF — malware analysis report

Static analysis result for SHA-256 6d8e0650a3e671bc…

MALICIOUS

PDF

9.6 KB
MD5: a321c41e693e9edf7ecc67b6dd07f3ee SHA-1: d54809719ef69b77be49d92d8670a0f9436ae736 SHA-256: 6d8e0650a3e671bce15e1f8956afb8af1100600fac15ecc0f2fb274cf3e2cf85
278 Risk Score

Malware Insights

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

The PDF contains JavaScript that exploits CVE-2007-5659, specifically targeting Adobe Reader versions within a certain patch range. The script decodes a payload and contains an embedded URL, http://gidllzcebzzi.com/nte/tuta8.exe/eH0881184bV0100f060006R816af5f6102Td3773181203l000cKfb081248, which is used to download a second-stage executable. The ML classifier also strongly indicated maliciousness.

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.
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER
    PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final exploit stage.
  • 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.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed 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.
  • 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://gidllzcebzzi.com/nte/tuta8.exe/eH0881184bV0100f060006R816af5f6102Td3773181203l000cKfb081248

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
b9a85ee399db318b3ad68d0755effe289a645a7404fad2094712c8a3fd042920
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 244 bytes
generic_stage_recovery_000.js
42e1f77e2ed23e12befc24f69b25b1726ec3445e5863b9fab5498a7bb2b67044
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 7 at offset 0x19B 234 bytes
annotation_subject_callee_hex_stage_000.js
2f167e444fefaa31064a9a89e56b48665b4fe9c514ad4b722e7480357be1e385
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5181 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
81b65c89a7ec42fc8fcd66259c0dcf4fefb4bab81851fda41a52cabf46e095b2
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2CA 12331 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).
deobfuscated.js
5d5bff054bf675d8d9c041efad7aa82758dea9bb0d5910ef8578363284a88063
deobfuscated-js PDF JavaScript deobfuscation pass 71905 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).